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View Full Version : Intersecting polygon rendering (vague title i know)



peter66
09-16-2005, 12:42 AM
Hi, I'm going to simplify things so I can actually ask this question. say you go into modeller and you make on layer1, a hollow cylinder. And on layer2, you make a plane.

You then take them into layout and you sit the plane down to act like a flat water surface. Then you plonk the cylinder down vertically into the water. So if you look straight down at the cylinder, you can see inside it but not all the way through it because the water surface is intersecting the inside.

Still with me?

Good.

I want to make it so I can float the cylinder around as if the bottom of it is sealed so that no water would be inside it and yet there's some cylinder inside the water.

Is there anyway of rendering it so you don't see the water surface inside the cylinder? I do however want to be able to see the reflections of the cylinder on the water which might rule out the option of rendering the cylinder and the water in seperate passes...

cheers
Pete

Surrealist.
09-16-2005, 01:21 AM
Well here's a guy I remembered tryng to float his boat. Think he wound up going for the compositing option though.

http://vbulletin.newtek.com/showthread.php?t=34511&highlight=boat

There might be an idea or two in it.

Regarding the separate passes, I believe you can check unseen by camera and still get the reflections, in fact I did a test on that.

Here at the end of this thread:

http://vbulletin.newtek.com/showthread.php?t=38258&highlight=unseen+camera

dee
09-16-2005, 05:19 AM
take a look at the Shift BooleanTexture-plugin:
http://www.flay.com/GetDetail.cfm?ID=1809

duke
09-16-2005, 05:48 AM
I just did a test using that plugin.

-Make a closed poly object in the shape of your boat as though you were going to do a normal boolean in modeller - as in if you tried to boolean out your actual boat model it would only cut out the inside of the wood planks or whatever you're using.
-Use this hull in layout parented to the boat and switch on unseen by cam, rays, and all shadow options off.
-Add a clip map to your water and use the shift boolean thingo (as a procedural). Choose outside and the boat cutter/hull object.

This works with subpatch objects and displacements :)

maxxwv
09-16-2005, 06:01 AM
You can always simplify things a bit - make a clip map the shape and size of your object (boat, cylinder, whatever). Apply the clip map to the water plane, and parent the clipmap to the penetrating object. That way, the water plane is clipped out of the boat no matter where you move said boat, and if you have to share the scene with someone without ShiftBooleanTexture, you won't have any problems.

duke
09-16-2005, 06:17 AM
You can always simplify things a bit - make a clip map the shape and size of your object (boat, cylinder, whatever). Apply the clip map to the water plane, and parent the clipmap to the penetrating object. That way, the water plane is clipped out of the boat no matter where you move said boat, and if you have to share the scene with someone without ShiftBooleanTexture, you won't have any problems.

But you can't move it anywhere. If you want any bobbing motion or displacement in the waves house do you account for the changing intersecting cut-out? This is the point of the shiftbooleantexture. A clip map method will only work if the intersecting shape remains constant.

Lightwolf
09-16-2005, 06:20 AM
But you can't move it anywhere. If you want any bobbing motion or displacement in the waves house do you account for the changing intersecting cut-out? ... A clip map method will only work if the intersecting shape remains constant.
Not really, in the simple caseof a cylinder, if you use the object itself as a reference item for the clipmap projection it should work.

Cheers,
Mike

maxxwv
09-16-2005, 04:06 PM
Correct me if I'm wrong (don't have LW open at the moment), but if you use the boat object as the clip map's reference object, it basically parents the clip map to the boat object. So if you turn the object, the projection plane of the clip map should move with it, right? Assuming you're using Planar Projection from the Y axis.

Or am I totally nuts? (I spent all day helping a friend move, so the latter is totally possible right now...)

hesido
08-16-2006, 02:30 PM
Boolean Texture is the best solution, ever. :)