Class A Surfacing Defects

[seamuslloydwhite]

Hi, I've been attempting to do some approximately Class-A surfacing in Fusion by creating manual G3 curves using control point splines. I've been following along with this guide (https://www.youtube.com/watch?v=BFHaQGhxURs&t=776s), and have finished the model, but there are some irregualrities in the surface that I can't figure out how to get rid of. Any idea how to remove them or if they will appear when CNC machined? Thank you!

[johnsonshiue]

Hi! Could you be more specific on the irregularities on the faces? I would like to understand it better.

Many thanks!

[seamuslloydwhite]

Hi,

Of course, thank you for taking the time to reply. It's a small thing as pictured in the screenshot, it looks similar to aliasing or like the edge is pinched when zoomed in, and like a hard line between some of the outside edges in the reflections on top of the body.

Thanks!

[evanp4509U4JZ]

Have you tried a zebra analysis or a curve comb analysis?

Sometimes the visual representation isn't what is actually there. I don't really know how to interpret the info from those things but they may shed some light on the problem.

[seamuslloydwhite]

Hi, thanks for the reply, I have yes, the curvature combs aren't the cleanest but I'm not entirely sure why, and the zebra analysis is a little bit rough before stitching and then a bit worse after stitching. I've attached a couple of screenshots of the zebra combs before and after stitching and the isocurves after stitching

[seamuslloydwhite]

I've been working through it again stage by stage and what I'm finding is that it seems to be ok up until the point of mirroring or stitching - I'm wondering whether its due to Fusion's surface stitching tolerances? I've attached two images, one before mirroring and the other after. Using a join with the mirror, creating a solid body and mirroring that, or mirroring the surfaces and stitching them afterwards doesn't seem to make a difference. It almost looks like gaps are opening up when stitching? Thank you!

[John_Wright · Accepted solution]

Try adjusting the "display detail control" on the body (right click on the body you want). It may just be a rendering display issue, rather than a mathematical problem with the surfaces.

[John_Wright]

Having said that, the curvature analysis and zebra doesn't look that great.....

[seamuslloydwhite]

Thank you! That's fixed it! I've subdivided again and cleaned up the workflow a bit and that's improved the zebra analysis, I'll keep working on evening it out for the curvature analysis

[TrippyLighting]

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@seamuslloydwhite wrote:

...I'll keep working on evening it out for the curvature analysis

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I wouldn't. You are fighting an uphill battle, trying to improve it from where it is. More "subdivision" isn't going to get you a better result.

[seamuslloydwhite]

Ah right, thanks, I'll do some more research and see what I can do

[seamuslloydwhite · Accepted solution]

If anybody is curious, lofting from a different direction has given me a better result and helped clean it up a bit