Extrude from plane to complex surface

[nicco42]

I'm currently designing up a set of sunglasses frames that I am planning on casting - I will be using CAM to machine mould boxes; then making silicone moulds from that.

I'm having trouble making the model of the silicone mould - I want to create the shape that the mould will eventually take. When I've done this on more simple projects I would typically project up to the face of the body. In this case though, using a t-spline modelled object, it doesn't seem to want to work and keeps giving me errors.

Does anyone have any suggestions on why this isn't working for me? The sketch that I'm wanting to extrude is made from the projection of the body that I want to extrude up to.

I'm happy to upload my file here, but which format does every typically export to?

Thanks in advance,

Nic

[TheCADWhisperer]

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@nicco42 wrote:

I'm happy to upload my file here, but which format does every typically export to? 

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The most logical format is *.f3d

File>Export *.f3d to your local drive and then Attach your *.f3d file here.

[nicco42]

Thanks, TheCADWhisperer,

Attached now.

[nicco42]

If it helps, this is the end result I'm chasing; this was obviously a much simpler project, but the silicon mould and mould box arrangement is much the same.

Due to the conplex shape of the sunglasses frame, the only way I can think of to get the silicon mould component is to project up to the face like I'm trying to do; but yeah, can't get it to work. I've also tried extruding through and then cutting (through the combine tool) with the original glasses frame, but that doesn't work either.

Thanks again,

Nic.

[mavigogun · Accepted solution]

You're not going to like this.   Fusion (and most other CAD programs?) has difficulty with non-planar closely co-located compound curved surfaces- specifically, what occurs at edges where the forms match.    So, expect to see failures when attempting to Combine or Cut such surfaces- or with extrusions like this when the Extrusion edge matches the target.   

One (bad, in my opinion, depending on your need) option here is to fractionally reduce the size of the the Extruded Profile.    Another is to manually Split or Silhouette Split the target, then create a zero Offset Face of the needed surface.

See this post:

https://forums.autodesk.com/t5/fusion-360-design-validate/testing-the-cutting-edge-of-boolean-operat...

-and this post:

https://forums.autodesk.com/t5/fusion-360-design-validate/cut-out-irregular-shaped-body/m-p/8318719

[nicco42]

Hi Mavigogun,

Thanks for the links. Definitely looks about the same, doesn't it. It's a shame, because the workflow on simple parts from this stage is straight forward, but this is making it way more complicated.

But, I should be able to make a work around by either, like you said, shrinking one of my parts just a tiny bit, or just machining it from what I've got.

Thanks again for the help,

Cheers,

Nic.

[mavigogun]

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@nicco42 wrote:

But, I should be able to make a work around by either, like you said, shrinking one of my parts just a tiny bit, or just machining it from what I've got.

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I'd like to see how you manage it.   

(btw: folks intending to help will spend time reading threads- not knowing the issue has been addressed -until a post is Accepted, which places a green Checkmark next to the entry on the bulletin board)