STEP file importing as NURBS surfaces

[spettitt]

Hi there, I'm usually a Spotlight user but am starting to look at various 3D modelling tasks.

 

I also use Fusion 360 for most engineering/solid modelling operations (but will move some of this in to VWX when I'm faster at it) so I have a decent understand of solids, surfaces, meshes etc.

 

I have a STEP file sourced from Traceparts (a Lindapter CF212), which I can't attach here as .STP is not accepted. In Fusion 360, this recognises as I would like it to - a single solid body, and sectioning through it shows it as solid.

 

 

But importing the same file in to VWX using File > Import > Import STEP results in a group of 487 NURBS surfaces, and a clip cube shows it as hollow.

 

 

I've successfully brought in STEP files in the past which just leave me a Generic Solid or Solid Addition. Am I missing a preference somewhere to achieve the same single solid body, please?

[Andy Broomell]

Commenting in order to follow this thread and hear what other folks say.

 

I'm assuming you've tried selecting all the objects and doing Modify > Convert > Convert to Generic Solids, and/or making them a Solid Addition? I've had mixed success with this for imported items...

[spettitt]

1 minute ago, Andy Broomell said:

Commenting in order to follow this thread and hear what other folks say.

 

I'm assuming you've tried selecting all the objects and doing Modify > Convert > Convert to Generic Solids, and/or making them a Solid Addition? I've had mixed success with this for imported items...

Thanks, I have - Convert to Generic Solids gave me:

 

I couldn't find a menu command to try and make them a Solid Addition.

 

[Andy Broomell]

Model > Add Solids

[Pat Stanford]

I don't know why, but my guess is that based on the originating software the file is just the surfaces rather than a solid.

 

With the STEP model I am seeing the same as you.

 

With a Parasolid model of the same part I am getting a solid.  

 

Based on the huge number of ways models can be created, I think you just have to try different file types from different sources to find what works best for you.

 

And what works best will probably depend on the original source. Since Traceparts just takes models from the vendors and works them up, it is likely that the same file type will not always be the same between sources.

[Tom W.]

Or try Model > 3D Power Pack > Stitch + Trim Surfaces.

[spettitt]

58 minutes ago, Andy Broomell said:

Model > Add Solids

Sadly not: 

49 minutes ago, Pat Stanford said:

With a Parasolid model of the same part I am getting a solid.  

Yup, same.

49 minutes ago, Pat Stanford said:

And what works best will probably depend on the original source. Since Traceparts just takes models from the vendors and works them up, it is likely that the same file type will not always be the same between sources.

Yup, just interesting that Fusion took it as a solid and VWX didn't. It appears that trying in STEP or Parasolid to find what works for a given part is the way ahead. Wherever possible I'll get stuff from Manufacturers direct, but sadly lots of the geometry available seems to be mesh-based 😞

43 minutes ago, Tom W. said:

Or try Model > 3D Power Pack > Stitch + Trim Surfaces.

This did convert the Object type to a Generic Solid, which is helpful, but it was a hollow shell still. In some cases, this will be enough to make a STEP work.

 

Thanks everyone for the help.

Edited January 5, 2023 by spettitt

[Benson Shaw]

Probably best to try some of the other file formats. IGES?

 

But if the stp is format of choice . . .

 

Fail during Add Solids might mean mixed directions of the NURBS surface's normals.

To test, Select all the surfaces, and in OIP check the Show Direction button.

Verify that all the arrows point similarly, either all away from or all towards the clamp interior.

There might be some tiny surfaces. Zoom to verify.

Select any that do not conform, and reverse them via OIP Reverse Direction button.

 

Try the solid addition again. Or Stitch & Trim might help.

 

or  . . .

 

Sometimes there are too many surfaces to create Solid Addition in one go.

Try making subsets.  Note - sometimes this doesn't work at all:

 

Ungroup a copy of the clamp, repeatedly as needed until OIP shows everything is NURBS surfaces. (probably already did this)

Select a portion of the surfaces. Half? - contiguous is best. Add Solids. If success . . .

Extend selection to include more of the contiguous surfaces.  Add Solids again. Repeat until all included in new solid.

 

Or, start adding solids at one side, and start another addition at the other side.

Finally, add the two combos.

 

If success, it is probably already a filled solid rather than a hollow surface.

 

If hollow, try Modify>Convert>Generic Solids.

 

If that doesn't work:

Surround the hollow clamp solid with a bigger solid, eg cube.

Select the cube and the hollow clamp.

Model Menu>Section Solids. Use arrows to highlight the cube.

Result is a Solid Section object. Might be the clamp, but is more likely a cube with internal clamp shaped void.

In OIP, choose the Reverse Direction option. This reveals the solid clamp with no surrounding cube.

 

Unless you need to edit the components (cube and hollow clamp) of this new solid, use Model Menu>Convert>Convert to Generic Solids.

 

-B

 

 

Edited January 5, 2023 by Benson Shaw
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