Help with complex Sherman Tank Turret Shape (Convert 3D mesh to solid)

rustyncc1701

Hey,

I am trying to create a complex shape within BriscsCad, it a Sherman tank turret so its not regular at all, it has lots of complex curves and angles and dose not lend its self to simple extrudes, and other similar commands. I tried to using a sweep through cross sections and guidelines but I didn't have a lot of luck. The error messages were cryptic, although they hinted at over lapping sections, the turret does bend back so the middle section is wider than the bottom and top so I am wondering if that's the issue. Does the loft with guide lines have restrictions on the cross section shapes?

I have been able to use the 3D meshes to get the correct shape but I can't figure out how to convert them into a single 3D solid. I tried the DMSTITCH command but it does nothing and does not print out any errors. Whats the best way to convert a 3D water tight mesh to a 3D solid? How can I check the mesh to make sure its really watertight? I am constructing it out of several meshes, one of each side of the turret and the top and bottom.

Thanks,
Dale

Jason Bourhill

I would try using LOFT instead of SWEEP. With loft you can create multiple sections of different shapes, plus you can use guidelines.

Richard Webb

For complex models, this can be slow but: Explode the mesh to individual 3D faces and convert all faces to regions. Then run DMSTITCH followed by DMSIMPLIFY and, if you're lucky, you'll now have a 3D solid.

I've had this fail on some complex meshes, which likely was the fault of the mesh. Netfabb Basic (if you can still find it), Blender, and MeshLab have additional tools for working on meshes and can be used to smooth/decimate/repair them. Another software package(s) to learn.

Joe Dunfee

I just did an image search, and see several variations. It looks doable using the solid modeler part of BricsCAD. But, in general, BricsCAD is not the ideal modeler for something like this.

I think I would probably start with just extruding the top view profile, with some draft angle. Then, I would take some slices off for areas like the front of the turret where the big gun mounts. The large fillets would be the last part.

The big problem with meshes is that they are purely flat faces.

What is your end goal for the model? It may be that a mesh is all that you need anyway.

-Joe

Hans De Backer

Hello,
can you attach the 3d-mesh version that has the correct shape? There's a fair chance it can be modeled using 3d solids from the start, but without knowing the exact target (a quick search yields more than 10 turret variants), it is kind of hard to say...

rustyncc1701

Thanks for the replies. I'll attache some examples, but maybe you guys can answer a question for me. In the last CAD tool I used I was able to perform a sweep cut, can this been done BricsCAD?

Joe Dunfee

I am not certain it is a single operation off the top of my head. At the very least, you can simply perform a sweep, and then subtract that solid from another.

-Joe

rustyncc1701

Thanks for all the responses after getting a little more experience I was able to build my shape using 3D solids.