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View Full Version : Render-time booleans without Renderman?

kyleb2112
02-23-2008, 01:30 AM
Is there any way to make one object invisible where it bisects another object without using Renderman? Renderman calls it render-time booleans and it's described in this DT video:
http://www.digitaltutors.com/digital_tutors/video_details.php?v=935

Imagine a complex engine model where you could freely move a sphere with a camera inside through it, and the sphere hides the geometry so you get an updated cross section view of all the internal parts. I see stuff like this all the time, but not sure how it's done. I've been trying matte shaders but they seem to work only from side perspectives.
Bitter
02-23-2008, 09:14 PM
You can do this for a whole frame using a clipping plane. As for using a shape to cut it out, that's more complicated and I'm not sure how to do that other than compositing with a cross section rendered.
kyleb2112
02-24-2008, 06:34 AM
Well, here's a method I figured out where I'm using the lightInfo node connecting a hidden sphere through a condition node and feeding into an object's transparency. It pretty much fits the bill as far as cutting one object with another via shading networks, but it doesn't do that nice sealing up of the hole edges that Renderman does with it's render-time booleans. In other words you would see a nice smooth shape in the cut out region rather than the interior geometry. Any of you MR guru's know how to pull that off?

http://i29.tinypic.com/53acyo.jpg

Here it is animated:
http://www.youtube.com/watch?v=oGV6PsMuc2c
mental
02-24-2008, 06:49 AM
Try Binary Iris' Booltrace Shader (http://www.binaryiris.com/main/?id=BoolTrace) with Pixero's files (http://www.pixero.com/downloads_mr.html) for use in Maya. I have not used this shader before but I hope that is what you are looking for.
kyleb2112
02-25-2008, 08:27 AM
Sweet, I'll check it out.
Audellah
09-29-2008, 07:04 PM
Hi kyleb2112, I'm really interested in the shading network you built; can you write the datails ofthe connections used in the network?
Thank you!
reptil
10-03-2008, 04:20 PM
the puppet shader p_shader have p_CSG anyone try it ?
Puppet|
10-03-2008, 07:15 PM
p_CSG shader description:
http://www.puppet.tfdv.com/shaders_p/docs/p_csg.html
Audellah
10-06-2008, 03:57 PM
In the end i used the puppet CSG shader, but it has some limitations, like no occlusion...
Thanks
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