Introduction to Maya - Rendering in Arnold
This course will look at the fundamentals of rendering in Arnold. We'll go through the different light types available, cameras, shaders, Arnold's render settings and finally how to split an image into render passes (AOV's), before we then reassemble it i
# 1 19-11-2003 , 07:42 AM
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rain drops

I'm trying to make it rain on my T. rex. the rain comes down okay, but when it collides, it makes a new particle as a result of collision events, and its supposed to run down the sides like water droplets, instead it just falls through his skin and collects on his insides like he's a bucket. I think this is because when the new particle is born its already "in" the skin, so the collision is not computed. does anyone know of a way to solve this? is there an expression to put the new particle a little above the skin? any help would be much appreciated.

# 2 19-11-2003 , 10:50 AM
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I don't know the answer but would like to say even doing that is pretty cool I think..

# 3 19-11-2003 , 07:19 PM
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I actually figured it out, position = birthPosition + <<0,.05,0>>;
that puts it just above where it starts so it knows to collide with the first part, it now runs down the sides, but now I need to know how to make it stick to the surface as friction just isn't working or doing it right, find the solution to one problem and then you find there's another on the other side...
anyway, thanks for your reply, and thanks in advance for any other responses

# 4 19-11-2003 , 09:18 PM
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https://pilotltkettch.250free.com/raining3.zip
well, here's what I've got so far, using that creation expression, i just need to figure out how to make the drops stick to the skin a bit better, as friction doesn't do it right (it's already at .9 here). thanks for all replies, and thanks in advance for future replies. if anyone can offer help with the drop stickiness, don't hesitate to comment.

# 5 20-11-2003 , 06:19 AM
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Have you also tweaked the resillience and/or mass on a perparticle/object level as well?

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# 6 21-11-2003 , 01:28 AM
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yeah, I tried that, but it still falls the same way, changing those just adjusts the speed at which it gets there. but I was thinking, is there, first off, a way to get a particle to follow a surface and then either drop when it reaches the edge, or emit a new particle when it reaches there, or is there a way to get it to pull towards the object's pivot point (or just the surface) and then at a certain point, stop and drop? any help would be appreciated

# 7 22-11-2003 , 12:48 AM
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ok, I've been trying to use goals, inside the T. rex at certain points are locators, about 10 of 'em, that the particles want to go to. I was going to try and make it so that per each particle the goal weight would depend on the distance between itself and the locator. is goalpp per goal weight or for every goal weight? is it possible to this for each goal weight? is this even a good idea? thanks in advance

# 8 22-11-2003 , 01:08 AM
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the animation looks nice. I like it. is the rain falling off the body to fast at the bottom ? or is it not falowing the undercurve of the body to your likeing ?

# 9 22-11-2003 , 03:54 AM
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yeah, its not following the underside, like real water would, this has been driving me insane, I tried using goals, with the locators, but it didn't work, because goal weight is not per particle, and goalPP is for all goals, if there was a per particle per object one then it would work, but no. now I'm trying to make the actual body of the T. rex as a transform goal, they stick more, but they move in weird directions across the surface, not straight down but at diagonals. if any one knows a good way to solve this problem, well... I'd appreciate it a whole lot. thanks in advance

# 10 22-11-2003 , 04:21 AM
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I have a idea you might try.. how about having the tRex emit a radial field from the vertices. Have the field pulling in. Although you might run in to the problem of not enough dense geo there.. you could make a high poly dup and hid that in the render. Just a thought. I have not messed with dynamics much but I do know a radial field emitted from the vertex’s of the tRex would be like a static field pulling the water that was close on to it.. might be hard to get the settings right.

# 11 22-11-2003 , 04:35 AM
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that is an interesting idea, I just don't know how to get a negative radial (which would in fact be a newton field, that does the same thing) to do emit at the vertices, I'm sure there's probably a mel script somewhere, but I don't know enough about this to write that, because that does make sense, that's what i was trying to do with the locators, mimic the static field that makes water sticky. thanks for your reply

# 12 23-11-2003 , 01:39 AM
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ok, I think I've got it, i create a newton field, select both the field and the rex, go fields>use selected as source, and then turn on under special effects, apply per vertex, I'll post results as soon as possible

# 13 23-11-2003 , 01:44 AM
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DUH!!! I totaly forgot about "Use Selected as Source of Field"!

Good job, sorry I wasn't quicker with an answer for you on this oneuser added image


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izzylong.com
# 14 23-11-2003 , 03:19 AM
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cool. glad it worked. I was thinking about something like that for a static afect on hair. But I had not tryed it yet.

# 15 23-11-2003 , 09:24 AM
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ok, new problem cropped up, without apply to vertex, the field is placed in the average of all of the vertices, apply per vertex applies the force equally to every vertex, so, places with more vertices get more combined force (rain drops get sucked to the eye). is there a way to fix this? adjust the magnitude per vertex? an expression, painting it like weights? thanks in advance and thanks for previous replies

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