Simufact Welding 2022

Apex Modeler Tutorial

Introduction, Application overview,

Modeling examples
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2022 Simufact Welding

Table of Contents
1. Apex Modeler ........................................................................................................... 1
1.1. Introduction .................................................................................................... 2
1.2. Application overview ....................................................................................... 2
1.3. Modeling examples ........................................................................................ 10
1.3.1. Basic geometries ................................................................................. 10
1.3.2. Typical welding geometries ................................................................... 12
1.3.3. Welding assemblies ............................................................................. 15

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 Apex Modeler Tutorial
2022

1 Apex Modeler
2022 Apex Modeler Introduction

1.1. Introduction

Apex is an FEM software belonging to MSC Software™ portfolio, which consists of modeler and solver. The modeler
of Apex is recommended as modeling tool for Simufact Welding to enable meshing of welding parts, modifying
their geometry or also if needed designing them. The data transfer interface contains CAD data transfer and mesh
data transfer interfaces. The first covers many formats for importing of CAD files including Parasolid, Iges, Step and
Solidworks files, and by using the latter the mesh in bdf format can be handled. Besides the high control of the hex
mesh generation using seeds, surface meshes and edges, Apex offers reliable tools for handling the geometries like
Cleanup and Defeature of the geometry and also handy tools for modifying the geometry like Push/Pull, Split , and
Boolean operations. The goal of this manual is to learn how to create hex mesh for solid parts, that will be used in
the welding simulation. It will be focused on various techniques available in Apex, used for creation of hex mesh.
Therefore considerations of the requirements in hex mesh for welding simulation will be pushed to the background.
This manual is done using Grizzly Release of Apex. Please note that this tutorial is done by the Simufact team and
may not be updated with each Apex version, so if you face confusing symbols, buttons or different tool grouping etc,
please see the documentation provided by Apex.

1.2. Application overview

The main window of the application contains the header bar, which in the left has the File menu and other menus
(1) and in the right the measuring and moving tools (2). The Model Browser (3) is an interactive tree display of the
model data and hierarchy. The modeling hierarchy is defined by the organization in the CAD file that was imported
or during the geometry creation by using the tools provided in this application. Assemblies, parts can be added into
the tree. Surfaces and meshes etc can be shown and managed. The Triad (4) is an interactive tool, which is good for
positioning and rotating the model. Modeling tools (5) enable you to create and mesh geometries.

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2022 Apex Modeler Application overview

Figure 1.1. MSC Apex basic GUI window

• File menu (1):

Here you can create new or open existing projects. This menu contains also import and export interfaces for import-
ing both CAD or mesh. The CAD importing interface covers a large range of formats like Parasolid, Solidworks,
step and Iges formats. Meshes can be imported in bdf, dat and nas format. The hierarchy in the CAD file of an im-
ported assembly will be kept. After creation a mesh for a part, it can be exported as bdf file. Meshes for an assembly
of parts can be exported as assembly or also separately for each part.

• Measuring tools (2):

With the measuring tools you get information about length of a curve, angle of an edge or a hole diameter and also
you can measure a distance between two entities. The measured values that are displayed on screen can be copied
and pasted as inputs to tools that have measurement values as inputs.

• Model Browser (3):

In the model browser you find all geometries listed to parts, which can be also listed to assemblies. Right clicking
any entity in the model browser gives you good opportunity to manage the entity such as Delete, Show, Hide,
Show Only and Export. The model browser selection and highlighting are synchronized with the graphic display
in the model view. Single and Multi-selection let you make rapid changes on the selected entities. In the browser
header additional to the general visibility icons like Show All, Hide All and Show Reverse, there are two icons to
add a part or an assembly. Individual appearance options like Visibility, Color and Render Mode are also offered
beside each entity.

Only the current part is active. So if you want to make changes to a part you have at first to set it as current by right
clicking the part in the browser and then Set Current.

• Triad (4):

This tool allows you to manipulate the view of the model. If you click on the letter identifying a coordinate direction,
the model will be rotated so that the selected direction is positioned out of the plane of the screen. Clicking on any
axis direction results in rotating the model 90 degrees about that axis. Clicking and holding on any axis results in
the model rotating about that axis at a constant rate. Clicking on the center of the interactive triad returns the model
to an isometric view.

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2022 Apex Modeler Application overview

• Modeling and transform tools (5):

The transform tools allow you to move or rotate selected entities or also to make a copy of them in a new location by
activation the copy button before moving the entities. To switch to translation or rotation press T or R respectively.
Repeated T or R toggles between the axes of translation or of rotation. The transformation of entities can be done
by holding the translation or rotation axis and moving it to a desired location, or for more accurate transformation
by clicking the desired axis and entering a value there.

Figure 1.2. Transform tools

Initially, the manipulator is locked to the geometry being transformed. If you wish to adjust the position of the
manipulator without moving the geometry, click on the Unlock icon. This allows you to align the triad axes with
the direction along, which you would like to transform the geometry.

Before we describe the modeling tools it's important to know that after selecting any of them, its individual dialog
will be opened and in the dialog bottom you find Workflow Instructions and Keyboard Shortcuts which help
you in how to use the selected tool. Furthermore some grid and snap options appear in the dialog. So you can adjust
them to facilitate the drawing of a sketch. In general the left mouse button (LMB) is for selection of objects, the
middle mouse button (MMB) for confirmation of the selection or to start the operation, and the right mouse button
(RMB) opens the context menu. However, holding these buttons sets the functions of LMB, MMB and RMB for
window selection, rotation and translation of the model view respectively. As a selection help you find the picking
filters beside the opened tool dialog. This filters contain the suitable items for selection (e.g. solid, surface, or solid
face as shown in the figure below). Without activation any of these filters then every suitable item (solid, surface,
or solid face) under the cursor will be highlighted and so can be selected. Activating one of these filters will specify
only this item for selection.

Figure 1.3. Selection filter

In the modeling tools there are four main groups of tools; Geometry Primitives and Create (considered as one
group), Geometry Edit , Meshing and FEM Edit. The sketching tools in Geometry Create allow you to draw basic
two-dimensional geometry (point, line, spline, circle and ellipse) within any plane. The drawing plane should be
directly selected after selection the sketching tool. In this group you can also modify ( Chamfer, Fillet and Trim4)
2022 Apex Modeler Application overview

the current sketch or Edit the dimensions in the sketch. Immediately after closing the drawn sketch if it contains
closed loops then these loops will be changed to surfaces. All open loops will remain as curves and points.

Figure 1.4. Sketching tools

The second modeling group Geometry Edit allows you to make changes to created objects (points, curves, surfaces
and solids).

Figure 1.5. Editing tools

Two useful tools in this group are Geometry Cleanup and Defeature . The first tool allows you to repair imported
geometries, and by using the second tool Defeature you can remove small, irrelevant for the simulation, features.
Geometry Cleanup is very easy and helpful in case the imported geometry is not carefully designed. Rarely if
the geometry is very bad designed it could happen that another faults occur during cleanup, so please check your
geometry after cleanup if everything is OK: no cracks, spikes, missing faces or invalid edges etc. should be present
in the model, then you can go on. Otherwise you have to identify the faults using the options offered for this tool.
The most useful methods in Geometry Cleanup are Geometry Simplify (default) and the second method Find and
Fix small features. Often the first method Geometry Simplify, using the default tolerances or using other settings
suitable to your geometry, is quite enough to repair the geometry but if that doesn't fix the designing faults you may
use the second method. Find and Fix Small Features allows you to identify and repair faults of the types selected
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2022 Apex Modeler Application overview

that are smaller than the specified tolerance. Once geometry is selected (with Auto Fix disabled) a list of identified
small faults will appear in the model browser. For the method Find and Fix small feature we recommend at first to
try with enabled Auto Fix (disabled as default). If that doesn't help then you can repair the faults manually by using
suitable tools like Filler for cracked surface, Stitch Surfaces to stitch two free edges together and Split Surface
followed by deleting for spikes. More information about the options of Geometry Cleanup you find in the Apex
documentation.

The following figure shows the common faults in geometries that are not carefully designed:

Figure 1.6. Common faults in geometries

The tool Push/Pull is very handy to create solids from surfaces or also to modify the solids by picking a solid face
or solid edge and pushing or pulling it as shown in the figure below. For more options and capabilities of this tool
see the Apex documentation.

Figure 1.7. Push/Pull tool

Very important tool in this group is Suppress/Unsuppress , which you will use later to suppress some edges or
vertices in a solid to make it meshable. The tools Boolean and Split Tool are specified for solids and achieve
Boolean operations on solids and split solids respectively. They are useful for meshing by parts as you will see later.
Stitch Surfaces (particularly the option Unstitch) and Filler present another tools for modifying solids. Unstitch
separates the solid faces into surfaces (decomposes the solid to surfaces). Then you can remove or modify the
surfaces. And after that, either stitch two edges under Stitch Tolerance joining two surfaces together otherwise you
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2022 Apex Modeler Application overview

can fill the space between two or more edges with a surface by using the tool Filler . After joining the surfaces to a
closed volume (without any free edges), they will immediately be converted to a solid. You find more information
about all tools in this group and about their all options in the Apex documentation. The tool MidSurface represents
with help of Simufact Welding an alternative method for creating a hex mesh for sheets with a constant thickness.
With this tool a midsurface of the sheet is generated. You can also adjust the midsurface position over the sheet
thickness by changing the dimension appears between the solid face and the generated midsurface as shown in the
following figure. After that the created midsurface can be meshed with quads and the surface mesh can be exported
as bdf. By importing this mesh with Simufact Welding you will be requested to set a thickness and number of
layers and also to choose a suitable length unit. According to the given data, Simufact Welding expands the quad
mesh to hex mesh with constant thickness. Please be careful here when you import assembly, then it could come to
penetration of the meshes if the expanded thickness is bigger than the distance between two surface meshes close
to each other. Penetration can also occur if the surface mesh has T-joint as in the figure below. Inside-out elements
can also be generated if the thickness is big compared to a curvature with fine mesh.

Figure 1.8. Midsurface generation

Figure 1.9. Shell expand in Simufact Welding

Meshing Tools present the fourth group of modeling tools. Here you find tools for meshing by various element
types like Curve Mesh, Surface Mesh , and volume mesh and also Meshing Control tools like Seeding of an edge
and Seed Point.

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Figure 1.10. Meshing tools

The tet mesher Solid Mesh in Apex can handle and mesh almost all common welding geometries directly without
any changes. But more relevant for Simufact Welding is hex mesh and so the 2.5D Meshing in Apex.

2.5D Mesher creates linear hex elements with 8 nodes. In order to be meshable, solid should have isometric property
that means it should meet the following two criteria:

• Have at least two topologically similar opposing faces (same number of edges, vertices)

• Connecting faces between the two similar opposing faces should be four sided and free from internal loops and
splits

Additionally, the solid geometry to be meshed must be free from conflicting mesh constraints such as existing mesh
on multiple opposing surfaces of the solid.

After selection of the 2.5D Mesher a test procedure starts automatically and all solids will be proven for meshability.
They will appear in green, red or yellow for meshable, unmeshable because of geometrical reason or unmeshable
because of mesh constraints respectively.

Under Advanced Properties, you may define the Mesh Size with a slider bar or text field. Entering a mesh size of
0 results in the mesh size being calculated automatically for the selected geometry. You may also choose a Mesh
Method of Auto (Automatic), Paved, or Mapp (mapped).

Figure 1.11. Advanced properties of 2.5D mesher

With Mapp the elements follow the edges of solid faces with ignoring the element size. On the other hand, with
Pave the element size will be considered and created elements will be more similar in size. The mesher offers you
an automatic option (this is the default option), which creates a mapped mesh on all three- or four-sided target faces
and a paved mesh on the remaining faces.
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2022 Apex Modeler Application overview

Figure 1.12. Difference between mapp and pave mesh

Curvature Refinement allows you to refine the mesh in curved regions. When you enable Curvature Refinement,
the property panel expands to show two ratios that control the mesh in curved regions. The smaller the ratios are,
the finer the mesh in the curved regions.

The option User Defined Sweep Face allows you to choose the solid face that will be meshed at first and used as
starting surface mesh. Therefore if you activate this option you have to choose the starting face by displayed marker
(arrow) after selection of the solid. If one of the start faces is already meshed, then it will be the only available
choice of the two opposing solid faces. If more than one of the possible faces is meshed with non-mapped elements,
then it is invalid mesh topology and the solid will be yellow (unmeshable because of mesh constraints). In that case
no direction markers will be visible.

Surface Mesh allows you to mesh surfaces or solid faces with trias or quads or both. The surface mesh is used to
mesh the geometries used for boundary conditions for the welding simulation.

As control for the mesh you have Meshing Control tools: Seeding, Seed Point and Feature Mesh Settings . The
first allows you to define the number of elements along a solid edge. Many options can be used here to get good
mesh such as the number of uniformly spaced elements (Number of Element Edges) or the Size of uniformly
spaced elements (Control Point Size). Furthermore you may have more control on the distribution of elements
along an edge by using the available types of Bias Method. By Seed Point you can define a single seed on a point,
a node, an edge or on a surface, which will be later involved as a node in the created mesh. Feature Mesh Settings
is used to define meshing parameters for different types of geometry for feature based meshing like a number of
elements along a Fillet or Chamfer or the number of the circumferential element for a fillet or a Cylinder. More
about mesh control you find in the Apex documentation.

The last main group of modeling tools is FEM Edit , which allow you to modify the created mesh. The most
important tools of this group are: Node Move , Node Merge and Node Align . They are often used in the meshing
by parts (meshing by dividing non 2.5d solid to 2.5d parts), as you will see later, to pair the nodes from two meshes
and merge them together to be able to import them as only one component by Simufact Welding.

Figure 1.13. FEM edit tools

Node Move allows you to move a node along a surface or normal to surface and Node Align allows to move
nodes to a drawn path or existing curve on a solid face or a surface. Finally you may use Node Merge to merge
the equivalent nodes under a given tolerance together. Please note before merging nodes from different meshes, all
meshes should belong to the same part in the model browser. However the import interface of Simufact Welding
offers a replacement of the tool Node Merge. So if the distance between nodes is under certain tolerance then they
will be merged during importing in Simufact Welding and you will see the following message (please don't be

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2022 Apex Modeler Modeling examples

confused about the term conflict, unlike the term sweep, used in User Defined Sweep Face in Apex, the term sweep
is used here in other sense and it is equivalent to merge).

Figure 1.14. Node merging during geometry import in Simufact Welding

1.3. Modeling examples

The geometry data files which are used in these examples are available in the folder C:\Program Files\sim-
ufact\welding\<version>\examples\apex_modeler\<example name>\CAD-Daten and can be
found in Simufact Demos as well. The finish worked projects of the examples are also provided in folder C:\Pro-
gram Files\simufact\welding\<version>\examples\apex_modeler\<example name> and
in Simufact Demos. The use of the seeds will come up later in the examples, as the goal of the seeds is to deter-
mine the number of elements along an edge we sometimes use the term ,,number of seeds´´ in this documentation
instead ,,Number of Element Edges´´ (used in the Apex GUI). The purpose of this tutorial is to learn quickly how
to use Apex as modeling tool for Simufact Welding, so all examples done in this tutorial very well reaches the
meshing criteria required for Simufact Welding but none of the created meshes is calculated or numerically proven
in Simufact Welding.

Before you go through the examples, it is recommended to take a look at the Apex documentation. So if you open
the Keyboard Shortcuts under Help you find listed keyboard shortcuts which help you very much e.g. in the manip-
ulation of the model, picking or selecting objects in the model. Furthermore in the same documentation section MSC
Apex Modeler the following sections are relevant for our examples: Application Overview, Model Management and
especially the section Tools.

1.3.1. Basic geometries

In this example you will learn how to create a simple geometry and how to mesh it.

Open Apex GUI and save the project under the name e.g. ,,BasicGeometry´´. When you open the tools Geometry
Create in the modeling tools, a dialog with several sketching tools will be opened as shown above. At first you may
select the 2 Point Rectangle . Immediately after selection of the sketching tool you have to select the sketching plane
(as long as the project contains no geometries yet, you can select only a global plane). After that the selected plane
with grid will be displayed parallel to the screen. Now click once to define the first point (first corner of the rectangle),
then move the cursor and click again to define the second corner of the rectangle and hence complete the creation
of the rectangle. Immediately after the second click the dimensions of the rectangle can be change in the dimension
boxes assigned to the length and width of the rectangle.

You may repeat that to create a circle by using the tool Center Point Circle and to create a triangle you can use the
tool Polyline and to end the creation of the polyline you have to click the middle mouse button. At this point your
sketch should be similar to the following screenshot:

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2022 Apex Modeler Basic geometries

Figure 1.15. Simple geometries in Apex

Immediately after closing the tool dialog the contours will be converted to surfaces in case they are closed (unlike
open contours) and three Surfaces will appear in the model browser under the part item. Now the model browser and
the surfaces look like the following screenshot:

Figure 1.16. Surfaces after closing the sketch

As hex mesh is more relevant for Simufact Welding, so to create hex mesh we need to create a solid with 2.5D
property. For doing that please go to Geometry Edit tools and use the tool Push/Pull. After the tool dialog is opened
you can select one of the surfaces by clicking it with left mouse button. More surfaces can be added to the first selected
one by clicking them and simultaneously holding the Ctrl key. To remove a surface from the selection click it again
simultaneously holding the Ctrl key. After the selection you can enter a value in the text field or drag the selected
surfaces along the normal (displayed arrow) then at first a transparent preview of solids will be shown before you
confirm by left clicking on the model view outside the objects to complete this operation of solid creation. When the
surfaces are dragged to solids the three surface items in the model browser will be replaced by solid items and your
screen will look similar to the following screenshot:

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2022 Apex Modeler Typical welding geometries

Figure 1.17. Surfaces dragged to solids

The final step in this example is to mesh the existing solids with hex elements. When you open the Meshing Tools
and select the tool 2.5D Meshing an automatic procedure for checking if the geometries are hex meshable or hex
unmeshable will run. In your case all geometries will appear in green (i.e. they are meshable). In the 2.5D Meshing
dialog you may change the element size to a suitable value for your geometries (please note, a value of zero means
that the element size will be automatically calculated) and then select the solids you want to mesh. You can select
the solids individually or all at once from the model browser or from the model view holding the Shift or Ctrl key.
After meshing three mesh items will appear in the model browser under the part item. Finally your model should
look similar to the following screenshot. The created hex mesh can be exported as bdf file by right clicking the mesh
in the model browser or in the model view and then export. The exported mesh as bdf file can be imported into
Simufact Welding.

Figure 1.18. Meshed solids

1.3.2. Typical welding geometries

In this example you will learn how to import a geometry, to clean up it, and to use Suppress and Defeature tools.

Please be careful here to the current part (you can set any part as current by right clicking it and Set Current) because
if you create e.g. a surface using a plane from a shown solid but the current part is hidden then you will not see the
created surfaces in the model view, so as it is assigned to a hidden current part it will be also immediately hidden.

Go to File menu and select Import Geometry then with browse navigate to C:\Pro-
gram Files\simufact\welding\<version>\examples\apex_modeler\TypicalWeldingGe-
ometries\CAD-Daten\Parasolid and choose X_T files: BentSheet, Plate and Tube followed by open.
At this point you will get back to the importing dialog where you can import the geometry with/without the option
Clean on Import (we will let it selected). After Import the three solids assigned to three parts (BentSheet, Plate and

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Tube) will appear in the model browser and also in the model view. The next step is to clean up the geometry. That is
as mentioned before very easy, and helpful in case the imported geometry is not carefully designed. As usual open the
tool Geometry Cleanup then select a geometry by left click or more by window selection and then press the middle
mouse button to start the cleanup.

After importing and cleaning up the geometries you will go to Meshing Tools and choose 2.5D Meshing . Immediately
a checking procedure will run and all of solids will appear in red as unmeshable as shown in the following screenshot.
The bent sheet on the left has actually 2.5D property but some edges in it should be suppressed. So open again the
Geometry Edit and suppress the four edges of the curvature borders on both sides of the sheet, by picking them (In this
case the multiple selection by a window will fail to suppress them). Normally, by multiple selection by a window the
suppressing tool will check and suppress only unnecessary edges. When going back to 2.5D Meshing the first solid
will appear now in green and you can mesh it. The other two solids still appear in red, so you have to remove small
features, which are irrelevant for welding process namely the small bolt, small hole, fillet and chamfer on the plate
and also the small bores and chamfer on the tube. So go again to Geometry Edit and open Defeature . Then choose the
picking filter Faces and left click the upper or the cylindrical face of the small bolt immediately it will be removed.
Repeat that for all other small features mentioned above.

Figure 1.19. Imported solids

Now when you go to 2.5D Meshing all of your solids will appear in green as following:

Figure 1.20. Solids after selecting 2.5D meshing

Finally you may use at first the default settings (Mesh Size of 10 mm and Mesh Method is auto) for the 2.5D
Meshing and select the solids individually or all at once by a window. You can select them in the model browser
also individually or at once by holding the Shift key. Now you have meshed all your solids and the meshes look good.
Anyway you may need to take some control on the meshes. So right click the part BentSheet in the model browser
and in context menu click Show Only. You can change the part color to orange by using the color selector beside
BentSheet in the model browser. In the same manner you can change the appearance of the solid or the mesh or any

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2022 Apex Modeler Typical welding geometries

other object, displayed in the model window. At first change the Mesh Method to Mapp and increase the Mapped
Mesh Dominance level to 5 and by picking the solid again it will be remeshed with more regular mesh. After that
change to the tool Seeding and set in a number of elements of 2 and then pick an edge over the sheet thickness thus
the mesh of the sheet will be divided to two layers as shown below:

Figure 1.21. Meshed bent sheet

Now you may want to mesh the pipe with two layer but this is impossible in the same manner like in the bent sheet,
where you find a lot of edges over the thickness but here you don't find any edge over the thickness. Therefore you
have at first to divide certain solid faces to create edges over the thickness and then use the Seeding on them. So
show only Tube and change its color to light purple. Then create a surface like you did before in the example for basic
geometries and position it axially in the middle of pipe. In tool Split Surfaces choose the method Split Surface using
face. By the left mouse button select both frontal faces to be split and confirm your selection by the middle mouse
button followed by selection the created surface as a splitting face and also confirm by the middle mouse button. Thus
the both frontal solid faces are split. Now you can put seeds on the created edges and your part will look like the
following figure. You may delete now the created surface for splitting and close the Seeding dialog.

Figure 1.22. Splitted pipe to define mesh seeding

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The mesh of the plate with a hole seems to be good but if you want more layers over the thickness, you can also use
seeds on an edge over the thickness.

After creation of hex mesh for all parts you can export them individually by right clicking the mesh in the model
browser or in the model view and then export, or by right clicking the part and then export as bdf format.

1.3.3. Welding assemblies

In these examples we will concentrate, beside the managing of welding assemblies in first example, on the meshing by
parts as a solution for unmeshable solids and sometimes for enhancement of the mesh quality. Which will be shown
in the second example.

1.3.3.1. Propeller shaft bearing

This welding assembly contains supporting tools in addition to the welding parts and welding seams. The
supporting tools represent the boundary condition in the welding simulation and they should be meshed only
with surface mesh. Whereas the welding parts should be meshed with hex elements. After importing the as-
sembly PropellerShaftBearing.X_T, found in C:\Program Files\simufact\welding\<ver-
sion>\examples\apex_modeler\PropellerShaftBearing\CAD-Daten\Parasolid\, the fol-
lowing geometries will appear in your model view and the hierarchy of the assembly will be kept as shown in the
model browser.

Figure 1.23. Assembly after import in Apex

If you open now the 2.5D Meshing dialog you will see that some parts are unmeshable, namely MainPlate, Shaft-
Bearing, OuterWall, Beam0 and Beam150. That is because OuterWall, Beam0 and Beam150 have too much edges,
whereas MainPlate and ShaftBearing have some small features. At first clean up all geometries and suppress all edges.
Suppressing all edges will make OuterWall and the beams meshable. To make the other parts meshable, right click the
part Bearing and show only then use the tool Defeature to remove the chamfers on MainPlate and ShaftBearing, and
also the small bore in the ShaftBearing. After suppressing the edges and defeaturing the small features your model
looks like the figure below:

Figure 1.24. Assembly after clean up and defeaturing

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Go to Surface Mesh and change the element size to 8 mm, the Mesh Type to quad and the picking filter to Faces and
pick the outer face of the solid ShaftBearing. After that go to 2.5D Meshing and set the element size to 25 mm and
pick all geometries of the Bearing (note that the surface mesh is adopted in the hex mesh). Show only the Weldseams
and change the element size to 3 and mesh all of them. Now show again the part Bearing and you will see that the
meshes of Bearing seems to be a little bit coarse in comparison to Weldseams and apart from ShaftBearing all are
meshed with only one layer of elements as shown in the figure below:

Figure 1.25. Assembly after meshing

To control the number of element layers for sheets you can use seeds with 2 elements on the edges over thickness as
you did before in the example ,,typical welding geometries´´. To make the meshes between the parts of Bearing and
Weldseams more suitable for the welding simulation we have to refine the meshes near the Weldseams. For doing
that you can prompt set seeds using the Control Method "Size of uniformly spaced elements" with Control Point
Size of 8 mm on the edges of Beams, contacting the Weldseams. On the MainPlate and OuterWall we don't have
edges near the Weldseams. Therefore you have at first to split the surface of MainPlate and of OuterWall using this
time the long edges of Beams, contacting the MainPlate and the OuterWall respectively. As a result you get edges
for suitable seeding as shown in the following screenshot. Please note that splitting the opposite face of a solid will
leads to unmeshable solid therefore if necessary suppress all other egdes. Finally set seeds with the previous settings
on the created edges.

Figure 1.26. Assembly with defined mesh seeds

Now you have already meshed your model with hex mesh and you may need also to mesh the supporting tools (bound-
ary conditions). These tools have to be meshed only with surface mesh. Show only these tools and then go to the
Surface Mesh and change the Mesh Size to 15 then select all of them by window. At last close Surface Mesh and
show all objects in your model.

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Figure 1.27. Completely meshed assembly

Current Simufact Welding version allows you (as default importing option) to import multiple meshes, saved in a
bdf file. You can by using the option "Import as single body" also import multiple meshes in a bdf file as only one
mesh and thus only one geometry even if they do not share nodes or if they are not connected. If you want to export
two meshes as only one geometry to Simufact Welding, say, the MainPlate and OuterWall are done in a previous
welding process and they should be considered as one geometry in Simufact Welding. You can do that in two ways:
merging the two solids together followed by partitioning the solid to two cells and the second way is to pair the nodes
in the contacting area of the two meshes before you merge the nodes by defined tolerance together. The second way is
similar to what you will see in the next example "Trailer Light Box" in the meshing by parts, therefore we will describe
here only the first way. So Show only OuterWall and MainPlate then go to Boolean in the Geometry Edit and merge
the both geometries together. After merging, the solid of MainPlate in the Model browser will disappear because it
was moved to OuterWall. Since the resulting solid is not meshable the meshes will completely disappear. In the Split
tool you find two options for the Split Behavior: Partition and Split. You will use the Partition which divides the
solid to cells without to decompose it completely. Thus after suitable partition the solid will be again meshable and
after meshing the meshes of all cells are connected together as they are one mesh. Change the Split Methods to Split
using Surface and pick the solid then MMB and as splitting surface pick the inner face of the OuterWall followed by
MMB. At this point the solid is divided to two cells by a dashed line. If you go to 2.5D Meshing tool and pick the solid
only the OuterWall cell will be meshed, whereas the MainPlate cell will be appears in yellow (unmeshable because of
mesh constraints). Change the picking filter to Cells and pick at first the MainPlate cell then the OuterWall cell. Now
you have meshed these two cells with connected meshes as they are only one geometry.

Figure 1.28. Meshed main plate and outer wall

Regard the supporting tools you can assign a group of them to a new part and then export them as only one part or you
can export every mesh individually. When surface mesh is imported to Simufact Welding then you will be requested

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to either convert the surfece mesh to volume mesh or to import it as it is. Since for boundary conditions you need
only surface mesh then just import it as surface meshes. Thus be careful, that occurs always when you import multiple
meshes with some surface meshes as e.g. a control mesh (like in ShaftBearing).

Assembly import will be available in Simufact Welding in near future. When exporting an assembly you have the
choice of exporting the assembly either in a single file (Flat) or in so called hierarchical include file (Hierarchical).
The latter consists of a header bdf file and a folder containing the bdf files of the parts in the assembly. Currently
it is recommended to assign all meshes belonging to one geometry in your welding simulation to one part and then
either export the parts as bdf individually or export all parts at once as assembly. For the latter you will find all bdf
files of the assembly parts in a collecting folder then you can import them individually into Simufact Welding. When
importing the bdf files in Simufact Welding you can import all meshes, belonging to one part, as one geometry or you
can also import them as multiple geometries.In the folder C:\Program Files\simufact\welding\<ver-
sion>\examples\apex_modeler\PropellerShaftBearing\created-meshes\ you find the mesh-
es of the assembly exported as Hierarchical. During exporting and importing of the meshes please don't forget to
choose a proper unit system.

Figure 1.29. Hierachical export of meshes

1.3.3.2. Trailer light box

In this example you will learn the meshing by parts and some operations on solids.

In a new project import the geometry from the example Trailer light box which can be found in the Simufact
Demos. Before Geometry Cleanup and Defeature please zoom in as in the following figure and you will see two
CAD faults. Cleanup of the geometry will not remove any of them. Unfortunately Defeature is able only to remove
the lower fault, what make the need for the tool Push/Pull to repair the geometry. So please pull the edge of the upper
fault inside the solid to remove the fault.

Figure 1.30. Geometry faults after import

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Show only LightBoxInner, suppress all edges by using the default settings to make it meshable. Note that only few
edges were suppressed. Undo the last suppress and check out the option Keep vertices at curvature change and
suppress all edges again. Now this part is meshable and you can mesh it with element size of 5 mm. As usually desired
you maybe need two layers of elements over the thickness, so set two seeds on an edge over the thickness. Now this
part will look like below:

Figure 1.31. LightBoxInner after meshing

Next, you will learn the meshing by parts. Unlike the previous example "Propeller shaft bearing" we will use here
the complete splitting as an alternative method for the solid decomposition instead of the partitioning. Right click the
part Block, show only and set it as current. If you select 2.5D Meshing, the Block will appear in red because it is
not meshable. To make it meshable you have to decomposit it to simple 2.5D solids. So open the tool Split Tool (in
later versions it could be, all splitting tools are grouped together). Take a look again to the Block to make decision
how would you like to split your solid. As a hint for following node pairing by using control seeds or FEM Edit, try
always to get rectangular or simple contacting areas between the created solids and also try to create as less as possible
number of simple solids. For this block, it is reasonable to split it across its axis to create two solids. It is no matter
which Split Method do you use here, both Split on Plane or Split on Surface will give the same result. As a splitting
surface pick the small solid face (yellow arrow) as shown in the following figure. After that suppress all edges in both
created solids, then hide the small solid and unsuppress the edges indicated in green arrows.

Figure 1.32. Splitted block

After meshing of both solids with hex element with size of 7 mm you will see that almost all nodes in the contacting
area do not match together. To see that, set the model view in x direction and hide the small solid, thus the mesh of
the small solid appears as wireframe not matching the mesh of the big solid.

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Figure 1.33. Not matching meshes

To get better pairing between nodes of the both meshes activate User Defined Sweep Face and remesh the small solid
again using the contacting face as sweep face. Now the node pairing on the contacting area between both meshes is
quite good except for three node pairs, indicated in red on the following figure. To pair them, it is easier to move
them along surface using the tool Node Move in the tool group FEM Edit then drag each node and drop it to its
corresponding one.

Figure 1.34. Not matching node pairs

After that, it is very recommended to merge all node pairs to avoid all not matching pairs with very small gap between
the nodes (Simufact Welding can merge only duplicated nodes during the importing of two or more meshes as one
geometry). To do that, export the both meshes as one geometry by right clicking the part Block and export as bdf then
import it again (we do that because dependent upon Apex version, sometimes the merge tool does not allow merging
of two nodes belonging to different meshes). Then go to the tool Node Merge in the tool group FEM Edit and use a
reasonable Node Merge Tolerance to merge and delete the duplicated nodes. Change the picking filter to 3D Meshes
and select the imported mesh followed by middle mouse button. The merged nodes will appear surrounded by a blue
cycle as the figure below. Now you can export the mesh as bdf by right clicking the mesh followed by Export. Please
don't forget to choose a proper unit system.

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Figure 1.35. Marked nodes for merging

LightBoxOuter will be meshed also by parts but this time to enhance the mesh quality. Show only LightBoxOuter
and set it current. Suppressing all edges and vertices by window selection will suppress almost all unnecessary edges.
Sometimes few edges, dependent on the suppress settings, remain in the solid e.g. the two edges as shown in the figure
below. These two edges will make the solid unmeshable and have to be manually suppressed.

Figure 1.36. Not suppressed edges on LightBoxOuter

When meshing the solid by element size of 7 mm the created mesh has bad quality as shown below. For enhancing
the mesh quality you have several ways to do that: meshing with User Defined Sweep Face, creating of edges on the
surface, use of seeds on surface and also meshing by parts which will be a good choice for this part.

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Figure 1.37. Meshed LightBoxOuter

This time the decomposition of the solid will be done by tools Unstitch Surfaces and Filler . Before you do that delete
the created bad mesh and unsuppress again all edges. Open the tool Stitch Surfaces and change the method to Unstitch
Surfaces then choose solid faces like in the figure below and then press middle mouse button. At this point the solid
doesn't exist anymore and it is replaced by two surfaces in the model browser. Hide the small surface and then go to
Filler and by holding Ctrl key pick edges 1, 2 and 3, shown in the following figure at right. When you release Ctrl
key a new filling surface will be created. Repeat that for other free edges to enclose the surfaces. Finally, immediately
as all surfaces are closed, they will be converted automatically to solid. Now hide this solid and show only the other
surface. For this surface you have to cut and remove two pieces that originally belong to the surface done at first. You
can split them by using the method Split surface with a drawn path and then remove them and repeat what you did
for the first surface to enclose the surface and create the second solid of the part.

Figure 1.38. LightBoxOuter aftersplitting

Show both solids, suppress all edges and mesh them by element size of 7 mm and 4 mm for the big and small solid
respectively. To pair the nodes in the intersection faces use suitable seeds on the edges, say 55 seeds and 2 seeds on
the long and short edges respectively. The following screenshot shows your created mesh for LightBoxOuter. Finally
make sure that all two nodes of the node pairs on the intersection faces are equivalence (duplicate), so that they will be
merged together during the importing into Simufact Welding. Otherwise use FEM Edit to move and pair the nodes
on the intersection faces or export the two meshes as one geometry and import it again to be able to use Node Merge .

Figure 1.39. Final mesh for LightBoxOuter

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2022 Apex Modeler Welding assemblies

After meshing the main parts of the assembly you want to mesh the weldseams. This is very easy as long as they
have 2.5D isometric property. Show only them, suppress all edges and mesh them with hex with element size of 1
mm. For more complicated weldseams maybe you need to suppress edges and vertices manually to reproduce 2.5D
isometric property.

At this point the main work is done and you need now to mesh the boundary conditions namely Tools. For boundary
conditions we need, as mentioned before, only surface mesh. Show only Tools and then change to Surface Mesh . Set
mesh size of 5 mm and the Mesh Type as Quadrilateral and select all shown objects in the model view by window
selection. All boundary conditions are now meshed and they should seem like the following screenshot.

Figure 1.40. Meshed boundary conditions

Now you have finished the meshing of all objects and you can export the created meshes either as individual meshes of
solids, parts or as assembly as you did before. In the folder C:\Program Files\simufact\welding\<ver-
sion>\examples\apex_modeler\TrailerLightBox\created-meshes\ you find the exported mesh-
es of the assembly as hierarchical files and also the merged meshes of LightBoxOuter and of Block as bdf files (named
Part_from_NULLMAT1_1.bdf and Part_from_NULLMAT1_1 (2).bdf respectively). Please note that on-
ly boundary condition meshes, coming in contact with the welding components, are necessary for the welding simu-
lation. All other meshes of tools, not coming in contact with the welding components, will only slow down the simu-
lation without any benefits. But if you like, you can involve all tools in the welding simulation for presentation and
visualization purpose.

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