Dear All,

I am a beginner in opengl programming. The project is going to design an animation scene which looks like the virtual colonoscopy. I attached one photo from internet here(1st).
Since to make the scene is only a small part of my project, therefore I draw it out by using multiple torus(see 2nd attachment). However, the supervisor comments that it would be better with arbitrary shape of the tunnel instead of "round circle".
I have checked Internet for this week but no ideas came to me. The option of NURBS surface costs too much computing time to me. and it seems too complex or not possible to describe an arbitrary tunnel inner surface with more than 1000 vertices.
My question is: Could anyone here with more experiences advice me an idea of how to work this out? the 3rd attachment is to be the idea scene

Thanks a lot in advance

I don't have any experience doing this, but this has a little information about what you are trying to do.
I am assuming you would do something like start with your current torus and apply deformations to it along the way to make something more random.

There was a article about placing shaped objects (circles, whatever) behind the mesh and pushing the mesh out with the object to deform it (from the outside or inside), but sadly I cannot find it

http://mrl.nyu.edu/publications/proceduralshape/proceduralshape.pdf

you could build a cylinder that has no endcaps. texture the inside and you are done. you can deform the sides of the cylinder so that you dont have a perfect circle on the inside.

If you can use bump mapping you can bump map in combination with this probably to fairly good effect.

edit: or also similarly, generate a cylinder by continuously adding a new n vertex shape on the end with the vertices having some sort of random jitter. With smooth lighting that would probably be enough. Pretty sure this is what mmakrzem was getting at in the first place.