topic Re: Loft from surface fails on mirrored body. in Fusion Design, Validate & Document Forum

Loft from surface fails on mirrored body.

crogers1146 — Wed, 18 Jun 2025 00:34:42 GMT

So I cam trying to create a loft from a solid to a surface that was created with a surface tool based of a 3d scan.

The loft works on one side, but fails for the other mirrored side. Vid attached.

The lime surface was the original and works as expected, it's mirrored side fails. The mirror plane was created by the midplane command on the two outer side of the rectangle that lines up with the sketch mid. The lime side of the sketch is a mirror.

Any ideas?

(view in My Videos)

Re: Loft from surface fails on mirrored body.

davebYYPCU — Wed, 18 Jun 2025 03:22:51 GMT

Not surprised it fails due to the curve jaggies in the sculpted body.

Yes, making it into smaller bits does help.

That you got one good one, mirror it. Some pretty tight jagged curves in the surface profile and will be mapping curves that are causing the self-intersection (yellow preview).

If it is a symmetric overall job (brief check looks like it), only do one half, press the button for the mirror of the other side - near the end of the timeline.

Might help....

Re: Loft from surface fails on mirrored body.

crogers1146 — Wed, 18 Jun 2025 06:56:04 GMT

I probably should redo the surface and try to make it smoother.

You mean do the loft and then do a mirror on the feature? Because that surface that fails is the mirror of the good (lime side) side. That side was originally allot more jaggedy. Hence the confusion as i thought given that its a mirror of the good side, it should of worked.

Re: Loft from surface fails on mirrored body.

davebYYPCU — Wed, 18 Jun 2025 06:50:57 GMT

As I understand the movie, you got one side to work, Mirror the good one (body)

For your file, it appears that most of it is symmetrical, do all the stuff that is symmetric on one side of the model, Mirror Join those bodies, and then finish up with stuff that is not symmetric.

Mesh bodies that do not align (not even close) to the Origin planes would drive me nuts.

Might help....

Re: Loft from surface fails on mirrored body.

TrippyLighting — Wed, 18 Jun 2025 12:58:23 GMT

@davebYYPCU wrote:

As I understand the movie, you got one side to work, Mirror the good one (body)

Don't! Identify the root cause, fix it and then move forward.

The T-Spline based surface has way too many segments to be smooth and Fusion has no tools to alleviate that.
Work with spline curves on two planes. This requires an intermediate understanding of surface modeling, which is hard to explain in text.
Maybe I have some time later today for a quick screencast.

Re: Loft from surface fails on mirrored body.

crogers1146 — Wed, 18 Jun 2025 23:22:56 GMT

Interesting, I was about to redo by adding more smaller section to the surface thinking it would of resulted in a smoother/better face to loft from. So how should I try to create a face/point to since the Mesh Section doesn't seem to work here because its not a single flat surface.

Re: Loft from surface fails on mirrored body.

davebYYPCU — Thu, 19 Jun 2025 01:26:55 GMT

Correct, fixing a (sculpted body) or that curve comb in particular, is above my paygrade, a few would not appreciate a start over suggestion, over a workaround if it is suitable.

Re: Loft from surface fails on mirrored body.

crogers1146 — Thu, 19 Jun 2025 02:53:40 GMT

If I messed up, I appreciate a start over suggestion.

Re: Loft from surface fails on mirrored body.

TrippyLighting — Thu, 19 Jun 2025 11:13:53 GMT

As @davebYYPCU has already mentioned, when working of a scanned reference, it is paramount that the scan is aligned to the origin.

In this design, the scan is not aligned with anything.

I would create a construction plane (which is way easier if the scan is aliened with one, or two origin planes!!!) for the surface that I've highlighted in red as that surface looks like it is flat when looked at from the side. then I would sketch/trace the shape on that construction plane. Start with lines and arcs. If hat doesn't reflect the shape closely enough, add control point splines with as few points as you can get away with. Most folks use way too many points!

Just as with T-Splines, less is more!

The yellow surface can also be traced on another construction plane.