Patches Required for Boundary Conditions

Tips & Tricks
1

Good day,

Does anyone have a sure proof way of importing patches along with the geometry into PrePoMax. I usually use Spaceclaim to save my geometry as STEP file. However, when I import into PrePoMax, the geometry does not include the patches that I need to apply my boundary conditions. For instance, when we want to create a ‘washer’ face to apply a fixed boundary condition or an arbitrary patch (see examples shown below).

I realize that to a certain extent we can use the feature “Geometry-> CAD Part-> Split a Face Using Two Points” However, this is only possible where there is already an existing vertex point in the geometry and to draw straight lines only.

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2

You can use Part BooleanFragments - FreeCAD Documentation in FreeCAD for this purpose. Just create a sketch, select it together with the 3D geometry and use the tool.

3

try using IGES file format instead.

4

@Synt, unfortunately IGES format exported from SpaceClaim produces the same results ie. no patches

5

Understood; but I was trying to avoid this extra effort. It would also require creating either Compound Parts or using Contacts or Ties

6

Not if you just use Boolean fragments with a sketch on the surface:

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The other boolean tools (used on volumes) can cause this but there are some ways to avoid that as well.

7

HI arnie,

You could also select single faces directly with a negative angle.
By the way, a THICK PINCELL would be useful to allow fast selection.

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8

Yes, but it would make the edges jagged in the case of a curved (e.g. circular) patch. So it’s usually best to prepare the patches in CAD software before importing the model to PrePoMax.

9

I see; I will give it a try then. Thank you.

10

Yes, I have done it this way before, but it’s not the most efficient method and relies on the mesh edge shapes. But thank you.