Creating "Real" Drill holes for clean Step Export

Rhino Developer
1

Hi everyone,

we created a lot of Step File for Sheet metal production using Rhino Common.

Our general approach was:

  • extrude a Profile Curve as an Extrusion
  • change it to a Brep
  • select an Extrusion from the document
  • change it to a Brep too
  • cal the Boolean Difference from both.

If we export this File as a STEP file, the cut in drill holes are not “real” holes, but made out of two Half Circles (red an cyan)
The Edge curve is not a circle, nor an ARC

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Other Software packages can’t detect these holes to be drills - which raises the question.

How can we create “REAL” Round Holes and “Revolved” Holes through Rhino Common

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Not sure if this example is actually better - but the edge curves are ARCs here. This was created by the “_roundHole” command. Still the edges are split though.

This is an Example of a STEP File created by Inventor:

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It’s one Surface and 3 Arc Edges (also not a circle)

Thanks
Martin

2

@chuck, it this anything you know about?

3

I think STEP export splits closed surfaces because back in the day some
programs couldn’t handle them. I’ll see if it’s easy to change that.

4

There will be an option in v6 STEP export to split closed surfaces or not.

5

Hi Chuck,

What do you mean by “will be” - will be in the next WIP release or will be in the final V6?

Thanks
Martin

6

Hi Martin,

I made the necessary changes to the low-level export code already. Someone else will be adding the option to the export dialog. Once that happens you will be able to change the behavior. I assume within the next week or two.

7

Great! Thank you!

  • Martin
8

Looks like it’s in this week’s build. Please try it out and let me know if it does what you expect.

Thanks,
Chuck