How can we draw 3D solid arcs ?

[the_rising]

Hi everyone,
I am new to OpenGL. I am working on a project where I need to draw 3D objects used in construction industry like rods(solid cylinders). I want to know how can I draw bent rods (3D solid arcs) using OpenGL ? Earlier I was using DirectX APIs but there is no API for bent rods in it so I had to develop my own code but it was taking so much time to render those bent rods(3D solid arcs). I am working on .NET Platform and using VB.NET. All responses are welcome.

Regards,

[jide]

I'm afraid that you'll have to draw them manually. There's no real gl functionalities that are specialised for such drawings.
For bending constructions, maybe a bone-skeleton would help. So you always draw a 'normal' rods, that's not curved. Then you compute dynamically the distorsions with the bones rotating with the angles you want.
I'm not an expert in skeletal animation of meshes so I can't say more.

Hope that helps.

[jide]

well, I forgot to tell that the glu gives the possibility to draw cylinders but that won't allow you to transform them per vertex.

Additionally to what I said on my last post, surely vertex shaders are a good thing to perform such transformations.

[Aeluned]

You can model the arcs in a 3D modeling studio and then import them into your application (3D studio max or Maya would do the trick). This should be easier than plotting all of the vertices using math (if you're familiar with these studios that is).

A free modeler is Anim8or I think.
Good luck.