InstantMeshes quad convert to T-Spline?

[Anonymous]

I have an .STL file that I have exported from Fusion as a .obj, converted using Instant Meshes to a quad .obj and then imported into Fusion.  My problem is that I cannot convert the quad mesh into T-Spline.  When I try to covert the mesh, Fusion 360 crashes.  I've also tried to convert to a BRep using the quad mesh and Fusion crashes also.  My main goal is to get to a T-Spline so I can edit the design.  Does anyone know what I could be doing wrong or a different way of doing the conversion?

 This is what I'm trying to follow:

https://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/How...

[TrippyLighting · Accepted solution]

IIRC there is a setting in InstantMeshes that causes it to export many of the edges as "sharp". 

I opened your quad mesh in Blender and all the edges highlighted in orange are m marked as :sharp" when I export this from Blender with the "sharp" removed it imports and converts fine in Fusion 360.

[Anonymous]

Thank you Trippy.  Oddly enough the "sharp" option check box in InstantMeshes was unchecked.  I needed to check it in order for it to work but you pointed me in the exact location.  Thank you!

[subversivespeed]

This and checking "make pure quad mesh" got everything working correctly.. Great problem solving here! 

[Anonymous]

Hello,

Thanks a lot for this solution. This was useful to me. For my problem, I am now able to convert the quad mesh to T-Spline like in the second image.

Could you kindly tell me how you arrived at the third image? What steps did you take to go from the second to the third image?

Thanks in advance!

[TrippyLighting]

You'll have to convert the T-PSLine into a BRep.

To do so, find the T-Spline body in the browser, right-click on it and select convert.

[Anonymous]

Thank you.

[Anonymous]

@TrippyLighting - "when I export this from Blender with the "sharp" removed".

Can I please ask you how to do this.

Thanks,

Edward

[TrippyLighting]

In Blender select the object and hit TAB to go into edit mode.

Hit "A" to select all and then CTRL E. Select "Clear sharp" form the menu.

Hit TAB to go back to object mode.

Export as .obj.

[Anonymous]

I followed all of the instructions to convert my triangles to quads but each time, Fusion refused to accept the results.

It wasn't until I notice a small warning that flashed on the lower right of my screen for all of 1 second that I needed to set in Preferences that the imported mesh should NOT be converted to triangles.

What a stupid preference to set!!!

[TrippyLighting]

---

@Anonymous wrote:

What a stupid preference to set!!!

---

I could not agree more!

[fundamental4]

hi all,

(beginner user).

I need help with my file please. I still have the problem with the convertion.

I tried TrippyLighting  procedure, also I tried "Do not capture Design History" conversion, and I also tried using Blender, removing Sharp edges.

Checked "Triangulate mesh polygons" flag is not enabled.

When using Instant Meshes "pure quad mesh" is enable but I still can find some triangles in the final mesh.

Where is the error? Could you please help me?

file: https://a360.co/2OBiWUE

Thank you.

[TrippyLighting]

Can you make the original geometry (.stl or .obj) available before re-meshing in Instant Meshes available ?

There are no triangles in the object in your .f3d file, but a good number of self intersections. Those are the reason the quad mesh does not convert into a solid body. I think that can be alleviated by applying one or two smoothing iterations in Instant Meshes, bit I'd have to try this out.

Edit: Correction, I do see a few triangles.

[TrippyLighting]

I removed a couple of self intersection. Even in box view mode this is painfully slow.

Now it converts fine. 

[fundamental4]

Thank you for your help TrippyLighting 

How do you fix the problem? Do you just Delete the edges?

As those triangles were a few, I did delete the edges one by one, but it didn't work. The whole part had many yellow stars, appart from the triangles.

Attached the imported file into Instant Meshes. I did many test in Instant Meshes (with 0, 1, 2...10 iterations, low faces number, very low and also high...).  I tried it, but I can't, I don't know why.

It is very slow for me also.

Thaknk you.

[TrippyLighting]

The yellow stars are not a problem. They indicate areas where surface curvature will not be G2 but in a structure like this, that is to be expected.

Fusion 360 unfortunately does not highlight the area it sees the problem in, but simply inspecting the mesh I found it.

There are other areas that could use cleanup and If it was me I'd spend an hour or two cleaning up geometry.

[fundamental4]

Masterclass.

Thank you for showing us your criteria about when a file should be "manually" repaired  and how to do it.

Thank you for the long video, file is very slow. 

When you say "cleanup", what tool do you mean?

[TrippyLighting]

---

@fundamental4 wrote:

When you say "cleanup", what tool do you mean?

---

There is no "cleanup" tool. I'd manually modify the mash, delete faces, create new ones, as edges etc. to get a better mesh flow. Some of that will result if fewer yellow stars.

[fundamental4]

ok, thank you  TrippyLighting for your help.