How to extrude a shape to a volume

Question

I am currently trying to show a series of images that slightly differ from each other in a 3D view, and which contain lots of transparent areas (for example, points that move in time inside a rectangle, and I would provide a 3D view with all their positions over time). What I'm doing now is generate an image with the points drawn in it, create one Boxes of 40x40x1 per frame (or rectangular shape of 40x40), apply the image as a texture to the FRONT side of the box, and add the boxes to my scenes at positions (0, 0, z) where z is the frame number. It works quite well, but of course their is discontinuities (of 1 "meter") between the images.

I would like to know if their is a way to create an "extrusion" object based on that image so as to fill the space between the planes. This would be equivalent of creating one 1x1x1 box for each point, placing them at (x, y, z) where x/y are the point's coordinate and z the frame number. The actual problem is that I have lots of points (several hundreds, if not thousands in some cases), and what was relatively easy to handle and render with an image would, I think, become quite heavy to render if I have to create thousands boxes.

Thanks in advance for your help,

Frederic.

Answer 1

You could use 3d textue with your data (40 x 40 x N) pixels, N=number of frames.

But you still has to draw something with this texture enabled.

I would do what you are doing currently - draw quads, but no only along Z axis, but along X and Y too.

Each of N quads along Z axis would have 40x40 size, each of 40 quads along X axis would be 40xN size, and each of 40 quads along Y axis would be Nx40 size.

So for 2x2x2 textue we will draw 2+2+2 = 6 quads, and it will look like regular cube, for 3x3x3 points in texture we will draw 3+3+3 quads, and it will look like 8 cubes stacked into one big cube (so instead of 8 cubes 6 quads each we just draw 9 quads, but the effect is the same).

For 40x40x1000 it would be 1080 quads (reasonable to draw in real time imho) instead of 40*40*1000*6 quads.

I only don't know, if the graphical effect would be exactly what you wanted to achieve.