How can I emit particle from an object that has a texture and transfer the color texture to the emitted particles?

Hello Alvaro,
Attached is an example file which uses a ColorMap VOP to create a Cd attribute, which is pulled into the POP Network and assigned to the particles.

All the best,
Jenny.

asegura_plat
Hello Alvaro,
Attached is an example file which uses a ColorMap VOP to create a Cd attribute, which is pulled into the POP Network and assigned to the particles.

All the best,
Jenny.

hi there - i was curious, is there some way to edit this so that i can use an animated file sequence?

i'm looking to use this exact method. i'm trying to avoid having to use the slow point sop and pic function to get particle color from my “uvtexture projected” colored geo

Sure.

eetu.

fantastic! thank you so much. One more question

Can Alpha be added in this VOPSOP?

Before using your method I had been using the UVTEXTURE SOP set to perspective from camera and my matchmoved camera. This was being applied to my 3d model of a girl but the model doesn't completely match the actress (in size) that's in my footage. Therefore I wanted to try and get rid of the unwanted color information that was being projected onto the model, *such as buildings, car, sidewalk* whatever part of the projection was unwanted on the geo. Therefore, I took an alpha matte that I had made, for using as a mask in my MATCHMOVE and brought that into my COP NET, and applied that as the ALPHA to the FOOTAGE. And in the POINTSOP, used the ADD Color with a pic function and pointed that to a IMG COP, of my sequence. THEN USED the ADD ALPHA, and a PIC function, and pointed that to the IMG COP with the ALPHA…

I noticed that in the colormap node in the vopsop, it has the ability for RGBA?
The thing is, the way it seems to be set up is needing to point to an outside file… and specify the file extension, instead of being able to point to a cop. Would it be hard to implement pointing to a cop? would it be better to resave my footage with an alpha channel? can it be implemented to have a seperate pointer to my actual ALPHA footage that's on disk?

okay thanks again
J

itriix
Anyway to get that Alpha into this VOPSOP?

Probably something like this should work, I'm in a hurry and can't test it

eetu.

wow so fast, thanks so much Eetu!

I'll test it for u

and post my results

thanks so much

oh and in the Color Map basename… is there a way to point to a COP?…

I applied my Alpha inside the COP… technically i could just rerender my footage out with the alpha in the image. but just more for my own knowledge, i'd like to know if that's possible

yep it works

now, still curious about a couple things though…

is there a way to point the color base name to a COP? *for example, I had the tiff sequence and the roto as seperate tif sequences“, and then brought that into COPS, and used the roto as an alpha mask… can I just point to that final IMG?

and second,
what about being able to point to a seperate external alpha matte file on disk?
as in, point to the color tiff sequence as one file, and the alpha as another?

anyways, for now, i just re-rendered the alpha matte with the footage and used that and it works fine! ”the reason i'd like to be able to for example do it in cops though, is so that i can play with the mask, say blur it a bit, and see how that effects my particle emission, or grow or shrink the mask“…

stuff like that, instead of having to ”hardcode" it by saving out the alpha with the color sequence to begin with.

reguardless though, thank you soOOOOoooooo much for your help today

Hi,

I realise this is a bit of an old post but i was wondering if anyone could explain where the image link goes.

I've tried editing the Color Map basename field on the vopsop but it always reverts to $HIP/img/basename_

Any help would be really great.

Sorry if this is a stupid question still very new to Houdini

Sorry, i've now realised i can edit the Color Map basename field but if i link it to my image sequence it still doesn't work.

Is there somewhere else i'm meant to link the image to?

Again any help would be really great.