Revolve/extrude a 2D mesh into 3D?

OpenGL OpenGL: Basic Coding
1

Guys

I am in the process of writing a Finite Element Post Processor for an app I am developing.

The pic below shows the current state of play

http://www.cadfem.com/scrap.gif

Soooooo, here is what I need to do next.

Basically I want to turn this into a 3D model (its 2D at the mo)

So I need to ‘revolve - extrude’ the mesh about the left hand vertical axis. Simple enough but I am being lazy.

To clarify a little… If I copied the above mesh and created 18 revolved copies at 10degrees I would have a ‘fan-like’ 3D ish, structure. The only thing missing is the ‘joining’ lines of the outer surfaces. This is crude, obviously, because you don’t need the internal fan but my OGL code should take care of the internal face removal.

My question… Is there a way to ‘revolve’ the 2D group about an axis so that the external surfaces are automatically created?

I am thinking, kind of the same way you can create a triangle strip or fan … am I making sense?

I can produce the external polygons myself but it will take a day or two of coding (I will have to work out which lines are external). I was just wondering if there was something simpler to try. “Oh you need the — GL-Magic2Dto3D command” etc :wink:

Sorry if this doesn’t make sense…

Thanks for any input

Julian

2

Reading through the OGL Red book… It looks to me like there are no shortcuts. So i’m off to ‘do it properly’

Julian

3

Just to confirm your suspicion, there is no such magical command :wink: . It looks to me like you’ve got it figured out ?/.

Cheers.

4

Thanks

Yeah… lazy or what!

Job done and it was easy. Just worked out which edges were on the boundary of the 2D profile and ‘rotated’ copies to produce a new display list of quads.

2D to 3D in one asy move…

If there was a magic command it would make things too easy — and that would never do :wink:

Thanks again

Julian