Shell Problems with Surfaces

[chris82]

Hi all, I am having a very frustrating time trying to shell out a surfaced fuselage. We recieved the IGES file from another company andI was able to fix the surface geometry in order to make the part a solid, but now I am having trouble shelling the part out. I tried creating offset surfaces from the outer surface and removing the material, but they won't merge, and I have been doing one surface at a time. It's worked ok, but there are gaps that leave material behind. any suggestions? thanks! P.S. It's for a mold for a model of the Global Hawk, so it's a pretty complex shape.

 

[gkbeer]

Does it matter if some areas are not offset evenly.

I'm thinking that trying to make every inside surface exactly offset by some value, and merging them, might be more trouble than it's worth. Do what you can with offsets then trim them back as needed and fill in the gaps with whatever works.

 

[satish153]

If there is any geometry check error while fixinh the surface geometry of making solid it will trouble you in shelling it.

 

[magneplanar]

chris82,

I suggest you approach this in another way. You already tried to directly shell, and to offset. Now it is time to use the analysis tools. Select the surfaces, either one by one, or in a group, and use the offset analysis to see which of the surfaces is failing[analysis-->geometry-->offset]. You will see a crossing of the mesh lines where one ( or more )surfaces are unable to offset at the value you chose. You can then decide whether to offset the surfaces that will offset and rebuild the rest, or look into why those surfaces fail. You probably need to do some import geometry repair to fix the surface issues before proceeding to an offset surface.

Personally, I avoid the shell function. It has improved to some degree with each release, but I still don't trust it, nor do I want to risk failures later of features built onto the shell.

cheers,

M

 

[Asho Pulsar]

I got one imported feature, i just go to model tree n right click over the imported feature- click edit definition. At that instance one new menu opens like Geometryin the menu bar. In that i gone to surface n i selected all the surface of the imported feature. After that wats the thing to do to create same part.

 

[chris82]

Thanks for all of the help. I ran an offset analysis and the surfaces are a mess. Most of them are crossing each other when I try to offset just the required .125".However, I am able to offset just one surface at a time, but they don't mesh afterwards. If I were to offset them one at a time, is there a way to trim them together?

 

[gkbeer]

Thanks for all of the help. I ran an offset analysis and the surfaces are a mess. Most of them are crossing each other when I try to offset just the required .125".However, I am able to offset just one surface at a time, but they don't mesh afterwards. If I were to offset them one at a time, is there a way to trim them together?

Yes... and no.

That is what the merge function is for. I allows either the joining or intersecting of two surfaces. Merging will succeed or fail for the same reasons that the shell failed.

It may be necessary to trim / extend or otherwise manipulate the surfaces before they will merge successfully.

Edited by: gkbeer