Trying to randomize start frame of animated Bitmap on particles

Sputnikanimation · 02-28-2025, 09:13 PM

Hello,

I have a particle system with spheres that all have the same animated bitmap sequence on them. Right now they are all playing in sync and I want to randomize their starting point so they are all different.

I have found several threads on this but none of them have a solution or tutorial on how to do this.

I've looked at the UVW_gradient sample file and can't seem to get it to work with TY-bitmap IFL frames versus the gradient.

I'm not sure what I'm missing. If anyone knows of a tutorial or resource for this I would appreciate the help.

Thank you for your time,
James

Sputnikanimation · 03-05-2025, 03:45 PM

(03-04-2025, 05:09 AM)fruqanhamid I don't know what I'm doing wrong. I've set up a simple test with an IFL sequence using TYbitmap. I've got a custom float using particle age and I can see the UVW values are different on each particle. Yet they are still all in sync from the IFL 0 frame. I've attached my test file would greatly appreciate any help figuring out what I'm doing wrong. I feel like I'm being an idiot and missing something simple. But just cannot get it to behave like i need it to. Wrote:
(02-28-2025, 09:13 PM)Sputnikanimation Wrote: Hello,

I have a particle system with spheres that all have the same animated bitmap sequence on them. Right now they are all playing in sync and I want to randomize their starting point so they are all different.

I have found several threads on this but none of them have a solution or tutorial on how to do this.

I've looked at the UVW_gradient sample file and can't seem to get it to work with TY-bitmap IFL frames versus the gradient.

I'm not sure what I'm missing. If anyone knows of a tutorial or resource for this I would appreciate the help.

Thank you for your time,
James

You can randomize the start frame of the animated bitmap using a Mapping operator with a UVW Offset in tyFlow. Try enabling "Use Particle Age" and adjusting the offset with a random variation. Also, check the tyBitmap IFL frame mode to ensure it's set correctly.

Sputnikanimation · 03-05-2025, 06:32 PM

(02-28-2025, 09:13 PM)Ok I'm trying to render this out in Arnold and it seems like it's not working in Arnold. When I try out the Gradient tutorial file it works fine in scanline, but breaks when I try to render it out in Arnold. Is Arnold not compatible with mapping out particles by age or UVW.x? Thanks for your help, Sputnikanimation Wrote: Hello,

I have a particle system with spheres that all have the same animated bitmap sequence on them. Right now they are all playing in sync and I want to randomize their starting point so they are all different.

I have found several threads on this but none of them have a solution or tutorial on how to do this.

I've looked at the UVW_gradient sample file and can't seem to get it to work with TY-bitmap IFL frames versus the gradient.

I'm not sure what I'm missing. If anyone knows of a tutorial or resource for this I would appreciate the help.

Thank you for your time,
James

Sputnikanimation · 03-22-2025, 04:24 PM

I eventually figured out that this only works in the scanline renderer not in Arnold or Vray.

So just a heads up for anyone else with this issue - TYbitmap UVW.x channels won't work on other renderers.

***tyFlow*** · 03-23-2025, 02:52 AM

I can't speak for Arnold but tyBitmap works fine with VRay.

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