Tangent handles don't show up for all vertices in sculpt mode

[Anonymous]

In sculpt mode, only vertices that are at creased edges or edges of an open body have tangent handles. See screenshot below.

The tangent handles should be available for all vertices. Without them, the user has limited control over the curvature of the edges.

I've run into this issue multiple times where the  curvature of the edge was wrong and I had no way to fix it. I tried using the  scale and rotate tools from edit form on the edge and tried using box mode but I couldn't get the curvature how I needed it.

[TrippyLighting]

This is intentional as you should generally NOT modify the tangent handles of T-Splines and rely on other modeling methods to create the needed shapes. That is perfectly possible 😉

[Anonymous]

I have an organic shape with an undercut on it and spent over 2 hours trying to get rid of the undercut using a combination box mode, edit form (scale, rotate move), and every other tool available in form mode. I wasn't able to get the precision I needed and wasn't able to eliminate undercut without changing the part shape.

If there were tangency handles on all the vertices, I would have fixed it in 5 minutes. 

I found other users who've had this issue below:

https://forums.autodesk.com/t5/fusion-360-design-validate/change-edge-curvature/td-p/6619704

https://forums.autodesk.com/t5/fusion-360-design-validate/how-to-straighten-a-t-spline-edge-in-sculp...

While I believe the existing sculpt tools are powerful, I do believe adding tangency handles to all the vertices would even more control to the user to create exactly the shape they want.

I hope this feedback gets passed onto the product manager or devs for consideration. Thank you. 

[TrippyLighting]

Can you share your model and explain in detail what you are trying to achieve?

[adam.helps]

By default, the tangency handles are fully constrained so that you can get G2 (curvature) continuity along the edges. If we unlocked the tangency handles and you moved them, then you'd no longer have G2 continuity. By default, we don't display these tangency handles, In a meaningful sense, they aren't even there.

There is always a way to add tangency handles--use the crease command to crease the edges. If the edges isn't showing tangency handles after a crease, it will be due to nearby star points, and maintaining the surface around the star point requires additional constraints (roughly stated, the rule is that you aren't allowed to have T-junctions near a star point; if the tangency handle would cause a T-junction within 2 faces of the star, then we refuse to display it). If you crease a sufficient number of edges, eventually tangency handles will appear.

The main problem with using the crease command to add tangency handles is that creases are usually G0. If you keep your tangency handles along the same line (collinear), you'll still get G1, but we don't currently have automated tools to do this for you. If you want tangency handles that let you keep the surface G1, we'd have to implement a new feature. You could add that as a request to the ideas board.

[TrippyLighting]

The Idea Station was closed end of last year for good reasons 😉

[Anonymous]

Thank you so much for your detailed explanation Adam.

Yes, based on my understanding, I'm looking for tangent handles that let you keep the surface G1. 

To illustrate this, if you look at the attached image of a basic sculpt box, I want to have full control over any edge and be able to control it similar to how I can control a fit point spline.  That way I can get the edge exactly how I want it. Right now, I can scale, rotate, and move the edge, faces, and vertices with edit form but it's difficult to get the edge curvature and vertex position in the exact position I need. With tangent handles in conjunction with edit form, it'd be a breeze.

For now, I'm planning to use fit point splines with lofted surfaces to get the control I need. However, that's a slow process. With tangency handles, I'd get the speed of sculpting with the precision of lofted surfaces which would be pretty awesome.