## shaping the geometry matrix from jit.noise

Jan 29, 2011 at 8:16pm

# shaping the geometry matrix from jit.noise

Hi,

Rendering 3 planes from jit.noise resluts in a geometry matrix that looks like a cube. What I want to do is change that cube into a cylinder. I am multiplying Z plane with oval (oval is white, surrounding is black) and it doesn’t work. If I scale the Z plane with scalar, scaling works. If I scale Z plane with any matrix that has constant value in all the cells it works too.

In case you decide to check the patch, try different options from yellow umenu. You will see that “oval” option doesn’t work.

Thank you!

– Pasted Max Patch, click to expand. –
#54661
Jan 30, 2011 at 11:42am

read yair r.´s wise post here and see max example jit.gl.render.cyl

http://cycling74.com/forums/topic.php?id=6085

– Pasted Max Patch, click to expand. –

#196878
Jan 30, 2011 at 4:45pm

Thanks a lot! It seems I’ll have to spend some time on this. But do you may be know why my version is not working? I would like to understand what is going on… Because for instance if I make a plane (xyz; z=constant) and add noise to Z, then I can control the shape of the noise with a mask. The only problem in that case is that i can’t get rid of the plane…

#196879
Jan 30, 2011 at 6:21pm

Well, I don’t know the exact answer to the problem, but you should take into account that in OpenGL “0″ means “position 0″. When you filter the z dimension of the jit.noise with the oval shape, the vertices which fall in the black area do not dissapear: they are simply drawn at z position 0.
That’s why you see a plane. Maybe in your example it is difficult to see, as everything is “noisy”, I have attached another patch:”black” z values are drawn in the plane.

– Pasted Max Patch, click to expand. –

#196880

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