topic Can't create shell for this lofted object in Fusion Design, Validate & Document Forum

Can't create shell for this lofted object

zornzack — Fri, 24 Feb 2017 09:29:25 GMT

I have 7 sections and I can manage to create shell for 5 but not the remaining section that I've cut out from the main body.

Re: Can't create shell for this lofted object

mroek — Fri, 24 Feb 2017 10:16:48 GMT

You will need to share your model, or at least provide more information/pictures. No one can help you in the slightest based on the given info.

Re: Can't create shell for this lofted object

michallach81 — Fri, 24 Feb 2017 10:18:14 GMT

That's simple you've picked the wrong profile, try to start from the ninth section, and don't forget remove that spline in sketch #293. It may help, or may not.

If you don't know what I'm referring to that's fine because we don't know what you referring to either.

Re: Can't create shell for this lofted object

LMD001 — Fri, 24 Feb 2017 12:35:55 GMT

Hello @zornzack

Yes, or share you're model or do a ScreenCast or post some drawings, based on what you have provided it will be somewhat difficult to assist you.

Best,

Ludo

Re: Can't create shell for this lofted object

zornzack — Fri, 24 Feb 2017 16:28:57 GMT

Re: Can't create shell for this lofted object

Anonymous — Fri, 24 Feb 2017 17:39:30 GMT

As the error message "helpfully" states, try adjusting the values or changing the input geometry.

So it's either the value you're specifying for the Shell is too large,

Or the geometry (body) you're acting upon needs to be changed.

I would first try orders of magnitude for the Shell distance first, since that's easiest. That is, try 1mm, then try 0.1mm, then 0.01mm, then 0.001. See if any of those work. (You only tried 0.4mm)

If it's still not working, then there is something up with your body.

To my inexperienced eyes it appears the body more complicated than it needs to be, so that might be a hint.

Since we don't have your file it's a little hard to troubleshoot.

Re: Can't create shell for this lofted object

zornzack — Sat, 25 Feb 2017 07:23:47 GMT

Well that's the shape that I wanted and if I alter the shape it will alter the design right?

I've tried 0.4 mm or even smaller, it's just wont make the shell 😛

Its a boat hull which I have broken into 7 sections and I've managed to make 4 sections with shell. Only left 3 sections and this is really crazy.

Re: Can't create shell for this lofted object

LMD001 — Sat, 25 Feb 2017 08:32:20 GMT

Hello @zornzack

Would it be possible for you to share your model ? From the ScreenCast it is difficult to see what exactly is wrong with the Shell.

Best,

Ludo

Re: Can't create shell for this lofted object

jeff_strater — Sat, 25 Feb 2017 14:10:05 GMT

Hi @zornzack,

One thing to know about solid shell: It is a precise mathematical offset surface. This can be good (you are guaranteed exactly uniform wall thickness), and bad (it fails for complex geometry). One tool set that can help here is the analysis tools, under the "Inspect" menu:

Two tools in particular, Zebra and Curvature Map can help to show areas of very high curvature, or surface discontinuities that exist in your model:

Here is a random shape:

Here is it with Zebra analysis:

where the stripes are dense indicates an area of high curvature, and possible problem areas. Where the stripes don't line up indicates a discontinuity.

Gaussian curvature analysis is also useful:

The red end of the spectrum shows areas of high curvature.

Most likely your model has some problem areas, and shelling is going to be a problem. Sometimes you can fix the model so to eliminate those areas. Sometimes you have to resort to other methods (defining your own shell profiles and features to hollow out the inside).

As @LMD001 says, there's no substitute for the actual model.

Jeff

Re: Can't create shell for this lofted object

zornzack — Sun, 26 Feb 2017 07:51:01 GMT

Well Thanks Jeff, I have no choice but to take your advise and take the shell profile method. I have to retain the shape that i wanted but simple lofting it won't be able to do it.

Re: Can't create shell for this lofted object

jeff_strater — Sun, 26 Feb 2017 19:48:23 GMT

The offer still stands: If you want to post your design here, there are plenty of people that could offer some help. It might be possible to make small tweaks to your design, to get shell to work on it.

Jeff