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kfinla
10-30-2012, 04:56 PM
Hey Forum,

So I thought I was smart and was going to use an image sequence, or an image sequence converted to a weightmap to drive particle generation and location. The problem seems to be that particles seem to have no idea what these crazy UV or weightmap things are. I am using instances on particles at the moment. As soon as I convert my instance type polygons, surface.. anything but particles I see my weightmap.

I apply a weightmap to a particle instance system and my weightmap registers as 0 data.

So how do make particles spawn, or be constricted by an image/sequence?

XswampyX
10-30-2012, 04:58 PM
Use front projection and set it to multiply.....

..... I don't know why. :-P

Mr Rid
10-30-2012, 11:04 PM
Use front projection and set it to multiply.....

..... I don't know why. :-P

? Not working.

Have only gotten PFX to emit from planar maps (in birth rate texture, set to alpha), but even then, its iffy. And be sure to click 'calculate.'

erikals
10-31-2012, 12:12 AM
yup, same here, + UV maps won't work...

kfinla
10-31-2012, 07:22 AM
Thanks for the input. I wasn't seeing results with front projections and any blend mode set. Images sometimes make the particle jump, but you then check a box, like pixel blending and they disappear never to return. I'll try planar set to alpha can re calc. Procedural textures, work I know that.

Mr Rid
10-31-2012, 02:51 PM
I dont know what you are aiming to do, but workarounds come to mind, that may or may not help.

If you have a UV-mapped object animated, you could first render a lumi-only version of your object with only the black & white UV map, over a black BG. Then in a separate render, apply that previous render to a planar-mapped emitter card that fills frame, so you have an emission element that aligns with the rest of the scene (need to comp). Might even displace the card. But of course this is not a 3D emission.

For a proper 3D emission... I dont have time to test this wacky idea, but am imagining using the UV map to displace the negatively mapped portions of the mesh 'inward' along normals, to where they wont be seen. To get rid of the inwardly emitted particles, clone a second version of the mesh that is entirely displaced 'inward' (so it aligns with the negatively displaced polys of the first mesh) but with an 'erase' collision applied, that should hopefully erase the inward particles. Probably a fun mess. Again,this requires comping of separately rendered elements.

XswampyX
10-31-2012, 03:13 PM
Works here. ???


http://youtu.be/XQszpXVZX0U

erikals
10-31-2012, 03:16 PM
XswampyX, strange... only works with alpha here

Mr Rid, it should work, shouldn't be a problem. the only problem area could be the edges, but i doubt it.

kfinla
10-31-2012, 06:45 PM
Cool test XswampyX ! , any chance you could attach the .lws file? All my test seem super fragile. Maybe I need to re-look at my footage.. however my instances (using nodes works great with the same footage and give me the result I want. I just can't get the placement to translate to particles). Are you using LW 11.02 WIN 64? Are you applying the footage through the particle "birthrate" texture option? Pixel blending on and off has an effect I've seen too.

XswampyX
11-01-2012, 05:16 PM
Cool test XswampyX ! , any chance you could attach the .lws file? All my test seem super fragile. Maybe I need to re-look at my footage.. however my instances (using nodes works great with the same footage and give me the result I want. I just can't get the placement to translate to particles). Are you using LW 11.02 WIN 64? Are you applying the footage through the particle "birthrate" texture option? Pixel blending on and off has an effect I've seen too.

Here you go. You will have to use you own video.

108921

How did you know I'm using LW 11.02 Win 64?.... Spooky!

kfinla
11-02-2012, 07:06 AM
Thanks a lot XswampyX! It seems like the trick is you are using "PSMultiply", not regular multiply as the blend mode. I haven't tested this exhaustively but I immediately saw results with Planar and PSMultiply. That plus you are using a .mpg, , but I tried with a .mov and an image sequence and still got results.

kfinla
11-02-2012, 02:50 PM
Well I thought I could just change my scene at work to us PSMultiply and perhaps fiddle with projection types and I'd be good. Unfortunately no dice. There is still more to your simple scene, compared to my simple scene. I have instances in mine. You seem to be using FX linker.

I was able to get results modifying your scene at home on OSX even. But clearly there is more to it than I thought.

I need to investigate more what makes your scene work. Thanks again for sharing it.

XswampyX
11-02-2012, 05:27 PM
No, not FXlinker.... it's HyperVoxels..... 4,000,000 of them for the 20 second video. How about you post your simple scene and we have a look at it?

Good Luck!