maya particle

[surf]

I have a plane and a tga image (with alpha) on it. I have a particle emitter in the background. I want the particles to collide the image, but only where it is not seethrough, where can I set this? (these particles collide everywhere with the image now)

[HagerNYC]

Hey Surf. You might want to ask this in the forums at CGItalk.com . They should be able to help you. I don't know how to do that myself. Have you tried shaping the image plane to the shape of what you want the particles to collide with?

[Matt Grunau]

Surf, I don't think you can do what you are wanting with just a .tga file. You would have to map the entire image to a poly (or group of them) and then set them up to be collision objects for your particles. I don't see how you could do that with even using advanced surfacing incorporating the imbedded Alpha channel.

What you would need to do (unless Maya is very different in this regard) is to make a 3D object in exactly the shape you need, and tell the particles to bounce off that, and then position your camera close enough that the object is the correct size for it. You could trace it in Illustrator, import the paths into Maya and make a 3D image from that, then extrude it and you have something to work with. Problem with just an image file is that even though it contains an alpha and the portions of it in the alpha can be treated as being opaque, you would still be mapping it to a full set of polys to accomidate the full pic.

[bgundu]

Originally Posted by surf

I have a plane and a tga image (with alpha) on it. I have a particle emitter in the background. I want the particles to collide the image, but only where it is not seethrough, where can I set this? (these particles collide everywhere with the image now)

You can cheat this effect in Maya with a simple solution. Rough out the shape of the tgs image and put it slightly above the plane. Make this surface collide with the particles instead and don't forget to turn the visibility of this surface off.

Hope that helps.

Bob

[surf]

Originally Posted by bgundu

You can cheat this effect in Maya with a simple solution. Rough out the shape of the tgs image and put it slightly above the plane. Make this surface collide with the particles instead and don't forget to turn the visibility of this surface off.

Hope that helps.

Bob

I would do this, if the object was not a man, who doesn't stand in one place, so it would be hard to animate, the 3d shape. now I think, I will do the effect I want with layers, and not with collosion

[bgundu]

hmmm. I'm a little confused. I thought it was on a plane. Do you have a screen shot of what you are doing?

Bob

[Matt Grunau]

Originally Posted by bgundu

hmmm. I'm a little confused. I thought it was on a plane. Do you have a screen shot of what you are doing?

Bob

I'm a little confused too. surf, do you have just 1 .tga file, a .tga file sequence, or a video?

What bob suggested will work fine, but why would you need to animate it if you only have a still image that you want to bouncs things off?


Could you describe the shot or effect you are wanting? More detail the better.

[surf]

it is a video, which I have shot in a blue-screen, I have made the blue to 0 alpha and, export the video as a tga sequence. I have wanted to add a particle effect in maya, where the particles would collide only the man on the screen. but now I have exported only the particle as tga files too, and compose them in AE. I have just rendered it. awesome. I wanted just like that.

[Rich Lee]

can maya bump actual geometry in realtime? in OGL?....not at render time but in the viewport...i know xsi can do this using a push op and a image file...

if you can...then here is what i would do...

turn your image sequence into a black and white image...the background (your blue screen) being black...and your guy a solid white...basicly it will look like your alpha channel...

use that on a grid the same dimensions as your footage...and then subdivide the hell out of it...you will have to play with it and see....

then if maya is able to displace geo...then use the image sequence you have to displace the geo...but give it some rediculous number...so that the white part of the image...the guy...is displaced really far away from the background...then slide the grid around to where you would need the guy to be...

becuase the background is really far away...your particles will only collide with the part of the geo with the dude...

anyway... it might be a long shot in maya...this would totaly work in XSI.

any maya pros know if maya can do this? Bob?

[Matt Grunau]

Originally Posted by surf

it is a video, which I have shot in a blue-screen, I have made the blue to 0 alpha and, export the video as a tga sequence. I have wanted to add a particle effect in maya, where the particles would collide only the man on the screen. but now I have exported only the particle as tga files too, and compose them in AE. I have just rendered it. awesome. I wanted just like that.

Let's see the final shot! put it here or in the AE forum. Sounds cool.