Invalid T Spine Body Conversion - Autodesk Help!

[Anonymous]

When I try to convert a T Spline body, I'm getting the following error:

Error: Conversion error for: Head
T-Spline surface is invalid.

The conversion does not highlight any bad geometry.  When I try and Repair Body, I turn off all option except the Error checkboxes, Nothing shows up on the TSpline - which leads me to believe there's no problem.

But when I try to convert, I still get the error.  I've attached the file.  Thanks, I'm dead in the water at this point.

[NicolasXu]

Hi,

It seems the errors have been removed in the attached file. When I open the file, it’s in Sculpt environment automatically, then I click Finish Form and the bodies converted successfully.

Can you restart Fusion and give a try to see if you still see the problem? 

[Anonymous]

Nicholas - once I FINISHED FORM, the conversion did complete.

BUT, now I've lost my original T Spline bodies. In fact, it converted ALL
my T Spline bodies and I no longer have them. I'm left only with model
shapes.

Did you experience the same? Is this a Bug or the new design?

thanks, David

[Anonymous]

Nicholas - you gotta help me here.

If you're an employee with Autodesk - I need answers to this problem.  I've resolved the Conversion error with this file, but - now when the file opens, it always opens to Sculpt mode.

If I "Finish Form", it automatically converts the TSpline to a Body.  But the problem is that it's not leaving the original TSpline.  PLUS, it converts the ALL other TSplines in the file.

Please try this with the file I've attached previously.  I can't give up on this form - I've invested too much time.

I appreciate the help.  David

[bespenship]

Hi David,

I looked at your data, did the finish form, and the bodies convert successfully.  That said, I can still access the T-splines bodies (eyes and head) in the timeline.  Are you expecting them to be in the browser tree?

Nicolas and I work together at Autodesk - he's in China and I'm on the US west coast.  If you contact us directly (brent DOT espenship AT autodesk DOT com / Lixiong DOT Xu AT autodesk DOT com), we'd be happy top work with you on the phone to understand your issue and help you through it.

[jeff_strater]

Yes, this behavior can be a bit confusing at first.  In a Timeline (history-based) design, Fusion automatically converts TSpline models to BRep when you "Finish Form".  This is because TSplines are not history-based.  We do not capture edits to your TSpline body in the timeline.  So, when you edit the TSpline, we roll back the history, and you are editing the TSpline in a history-free environment.  You can do all the editing you want in this mode, which affects the TSpline body.  When you "Finish Form", Fusion converts the TSpline to a BRep (solid or surface) body.  Then, operations you perform on the BRep are captured in the Timeline history (shelling the body, adding Holes, etc).  The TSpline body is there, and can be edited via selectng it in the Timeline, right-clicking, and choosing edit.

If you do not need/want the Timeline history, you can convert your design to a history-free model, via the "Do Not Capture Design History" command in the "gear" icon at the right of the timeline.  Then, the TSpline body will always be available, even if it has been converted to a solid or surface body.  But, you then lose any advantage of the design history (the ability to edit the TSpline, and have later solid operations in the timeline automatically update).

Hope this helps a little 

Jeff Strater (Fusion development)

[dcgall]

Jeff - that at least explains the behavior.  As a newbie, I find dealing with the timeline features a layer of complexity that I don't want to deal with so I usually turn it off immediately, but in this case I did not.

Here's my next problem.  So I'm going to turn the Timeline off.  To do that, I have to FINISH FORM.  Well, that leaves me with a converted solid again.  

How do I turn the Timeline off and still maintain my T Spline?

thanks, David

[jeff_strater · Accepted solution]

Hi David,

You can go ahead do the Finish Form.  It will do the conversion, and it will look like the TSpline body is gone, but it is actually still there, just hidden.  When you turn off design history, you will then have two bodies in your Bodies folder - a BRep body (the converted body), and your original TSpline body (which will be invisible).  At that point, you can just delete the BRep body, make your TSpline body visible, and you should be all set.

BTW, we realize that this workflow is awkward, and are working to try to make it more understandable when using Design History.

Jeff