Randomly Twisting Sprites - Urgent

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Old 08 August 2008   #1
Rendering sprite wizard particles with mental ray?

sorry, see below

Last edited by nicodemus3d : 08 August 2008 at 01:57 PM.
 
Old 08 August 2008   #2
apologies if this is a really easy problem btw, it just has me a bit stumped

Last edited by nicodemus3d : 08 August 2008 at 12:36 PM.
 
Old 08 August 2008   #3
Ive got a set of sprite particles that were created with the particle tool (not an emitter), and i want them to each have one of a series of 15 tif images on.

Ive put the following expression to randomise the size and rotation of the sprites.

particleShape1.spriteTwistPP=rand(1,180);
particleShape1.spriteScaleXPP=rand(.1,1);
particleShape1.spriteScaleYPP=particleShape1.sprit eScaleXPP;

and used the sprite wizard to assign 1 of the images from the image sequence to each sprite particle randomly.

Now , the problem is:

it all looks great in my viewport, exactly how i want it, but for some reason when I render (with mental ray-hardware render wont work with my graphics card\) all of the particles have the same texture map and are for some reason are not being assigned a random texture from the image sequence as was set up in the sprite wizard.

Any ideas anyone?

Do you think that it might be just something to do with mental ray? because if it should work with hardware render I could go out and buy a new graphics card that works better with maya (the 8800 gts ive got is rubbish)

Last edited by nicodemus3d : 08 August 2008 at 01:59 PM.
 
Old 08 August 2008   #4
yea, unfortunately the PP attributes are not supported by the mental ray particle renderer.
the only workaround is to use the instancer with poly planes. There is a little more set up to get that to work though.
simpler method, since you only have 15 textures, is to emit 15 different particle objects.
MD


Originally Posted by nicodemus3d: Ive got a set of sprite particles that were created with the particle tool (not an emitter), and i want them to each have one of a series of 15 tif images on.

Ive put the following expression to randomise the size and rotation of the sprites.

particleShape1.spriteTwistPP=rand(1,180);
particleShape1.spriteScaleXPP=rand(.1,1);
particleShape1.spriteScaleYPP=particleShape1.sprit eScaleXPP;

and used the sprite wizard to assign 1 of the images from the image sequence to each sprite particle randomly.

Now , the problem is:

it all looks great in my viewport, exactly how i want it, but for some reason when I render (with mental ray-hardware render wont work with my graphics card\) all of the particles have the same texture map and are for some reason are not being assigned a random texture from the image sequence as was set up in the sprite wizard.

Any ideas anyone?

Do you think that it might be just something to do with mental ray? because if it should work with hardware render I could go out and buy a new graphics card that works better with maya (the 8800 gts ive got is rubbish)
 
Old 08 August 2008   #5
Thanks for the reply matt.

I had considered the 15 seperate emitters option, but wondered if that was an overly long winded way of doing it. Just so i know, will they render properly on the hardware render option if i had a graphics card that played better with maya and could hardware render? Im getting another computer in a week or so with a quadro fx 1700 in and im wondering whether to leave my particle pass till then and render it on that.

cheers
 
Old 08 August 2008   #6
I have occasionally had success with the hardware render buffer with a non quadro card.
The hardware renderer (accessed from render globals) can be hit or miss. You have tried the hardware render buffer - right? (Windows -> rendering -> hardware render buffer)
The real quadro makes a world of difference though - likely 70% of the people on here complaining of maya's instability are trying to run it on the wrong hardware.
MD

Originally Posted by nicodemus3d: Thanks for the reply matt.

I had considered the 15 seperate emitters option, but wondered if that was an overly long winded way of doing it. Just so i know, will they render properly on the hardware render option if i had a graphics card that played better with maya and could hardware render? Im getting another computer in a week or so with a quadro fx 1700 in and im wondering whether to leave my particle pass till then and render it on that.

cheers
 
Old 08 August 2008   #7
yeah i had a go, but got quite undesirable results.

Just to clarify, in theory the quadro 1700 should be able to render the particles I want with the hardware render yeah?
 
Old 08 August 2008   #8
well, yea, but I also depends on what you mean by undesirable. Do your images have a good alpha. Have you tried the depth sort and the use lighting options? If you have something else wrong, it may not necessarily be the gfx fault.
MD

Originally Posted by nicodemus3d: yeah i had a go, but got quite undesirable results.

Just to clarify, in theory the quadro 1700 should be able to render the particles I want with the hardware render yeah?
 
Old 08 August 2008   #9
might not help you much right now, but anyways, just to mention... finalRender from Cebas and renderman from Pixar handles sprites nicely.
 
Old 08 August 2008   #10
I used 15 different particle objects in the end and it looks great. As usual deadlines force us to fudge the results. haha. cheers guys
 
Old 08 August 2008   #11
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