How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

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nagmat84
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How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by nagmat84 »

I need to model a PartDesign body which is roughly a cuboid, but the surfaces are slightly sloped and edges as well as corners are rounded.

I understand that it is best to have a few sketches attached to the XYZ plane of the body's origin instead of basing subsequent steps on generated geometry. Hence I created three sketches which also use named constraints. This is how far I got:
Screenshot_20230527_130628.png
Screenshot_20230527_130628.png (111.51 KiB) Viewed 1040 times
You cannot really see it from the screenshot, but some edges are no straight lines but arcs. How do I proceed from there?

First I thought, I should proceed by padding the XY sketch. But how do I make that pad follow the sketches in the other planes?

Or do I have to pad the XY sketch, go with perpendicularly surfaces and then remove the superfluous parts of the body surface-by-surfaces and edge-by-edge? But I thought one should avoid that.

Any tips, hints and ideas a re highly appreciated. Thank you! (Model is the in attachment.)
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thomas-neemann
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by thomas-neemann »

nagmat84 wrote: Sat May 27, 2023 11:28 am
if this geometry is a solution, the workflow should also be applicable in part design
Bildschirmfoto_2023-05-27_13-52-21.png
Bildschirmfoto_2023-05-27_13-52-21.png (31.52 KiB) Viewed 1010 times
1351tn.FCStd
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Gruß Dipl.-Ing. (FH) Thomas Neemann

https://www.youtube.com/@thomasneemann5 ... ry=freecad
Bance
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by Bance »

Why make it hard for yourself? You can pad a rectangle and use drafts to angle the sides a pocket to angle the top then fillet....
cuboid.png
cuboid.png (33 KiB) Viewed 980 times
EDIT:

I didn't see the attachment, this workflow will not work for you.
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nagmat84
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by nagmat84 »

I will go with Bance solution. Thank you!
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FBXL5
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by FBXL5 »

With round sides the corners cannot be rounded as they should :( :
MPPT-FBXL5.png
MPPT-FBXL5.png (30.76 KiB) Viewed 682 times
This simple example shows perfectly that it doesn't matter how much FreeCAD improves, as long as the OCCT kernel fails to perform such relatively easy tasks, FreeCAD cannot reach the goal to become a professional application. :(

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papyblaise
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by papyblaise »

start with the cube with curved side but without the radius by making a pad with a 3.5° draft
then made the radius all around and the top, then the 3mm plate
The OCCt may have shortcomings, but we can always fix it
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MPPT PPB.JPG
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FBXL5
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by FBXL5 »

papyblaise wrote: Sun May 28, 2023 3:45 pm start with the cube with curved side but without the radius by making a pad with a 3.5° draft
then made the radius all around and the top, then the 3mm plate
The OCCt may have shortcomings, but we can always fix it
Yes it is possible to create round corners, but only if the radius of the side edges is larger than the radius of the top edge. In contrast the given sketches showed small radii for the side edges and a larger radius for the top edge.

Altering the shape with enlarged radii isn't a valid fix/workaround from my point of view.
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papyblaise
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by papyblaise »

that doesn't hold, you make a 40mm Pad with draft, you make the lateral fillets 3mm, you Pad the upper face of 10mm and fillets the top of 9.99mm
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FBXL5
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Re: How to create a body with non-perpendicularly edges in each direction in anefficientl and parametric stable manner?

Post by FBXL5 »

papyblaise wrote: Mon May 29, 2023 7:36 am that doesn't hold, you make a 40mm Pad with draft, you make the lateral fillets 3mm, you Pad the upper face of 10mm and fillets the top of 9.99mm
This is only acceptable if you don't care about tangential connections:
MPPT-PPB.png
MPPT-PPB.png (38.02 KiB) Viewed 408 times
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