Billboard particle capabilities?

General Forums Blender and CG Discussions
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Hi all,

Like I said in my previous thread, I’m a new blender user who’s currently evaluating it to see how well suited the program is for an upcoming short film I’m working on. So far, the results are insanely good. Blender rocks, overall!

My question here is about billboard particles. When I last tried them a couple of months ago, they seemed to fall just short of greatness.

In Maya, billboards are called spites and they have been a production staple for years to produce effects like smoke, pixie dust, clouds, motion trails, etc. They also have the additional benefit of rendering almost in realtime.

In Blender, Billboards seem to be gimped by lacking a few key features. It’s possible, however, that I’m simply missing the solution that’s right in front of me. At least, I hope so. :wink:

It’s been a while since I tried them, so I will simply fire out a list of questions, some of which are to just refresh my memory.

Can blender billboards use avi/quicktime movies with alpha channel?
Can these quicktimes’ starting frames be randomly offset?
Can billboards be assign random vales at creation-time for scale, speed, rotation, color gain, etc?
The BIGGEST issue (for me): Can I control opacity of each billboard over time? Can I fade a billboard in at the start of it’s lifespan and fade it out at the end? I know you can do that for many of the particle types, but I dont think you can do it with billboards. I hope I’m wrong. :slight_smile:
Can billboard colors be influenced by a color ramp over time?

If any of these areas are deficient, are they on the the roadmap to be implemented?

Sprites/billboards are a HUGELY powerfull particle tool, just so long as they are implemented fully. Overall the particle tools look awsome! It just needs a little extra push to make it truly great!

Thanks!

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You really should ask these questions in the relevant support sections, in this case that’d be " composition visual fx and rendering"

Can blender billboards use avi/quicktime movies with alpha channel?
I don’t think so, but you can do the same thing a different way…

you can use a texture split into a grid with each grid square becoming a “frame” in an image sequence. (see “UV split” in visualisation)

Can these quicktimes’ starting frames be randomly offset?

yes check the visualisation tab right beneath the “UV SPLIT” section They can be linear, random or based on angle…

Can billboards be assign random vales at creation-time for scale, speed, rotation, color gain, etc?

scale speed and rotation yes, colour… a bit of an issue for billboards… halos can do that though.

The BIGGEST issue (for me): Can I control opacity of each billboard over time? Can I fade a billboard in at the start of it’s lifespan and fade it out at the end? I know you can do that for many of the particle types, but I dont think you can
do it with billboards. I hope I’m wrong. :slight_smile:

That you can do with an IPO for alpha, it’ll use relative time ie particle age.

Can billboard colors be influenced by a color ramp over time?
No, that’s just not possible at the moment.

If any of these areas are deficient, are they on the the roadmap to be implemented?

So it’s really just the colour ramps thing that can’t be done as long as you are prepared to make tiled image cells rather than aviquicktime.

The fact that colour ramps aren’t available now makes me think they’re tricky to write in the current architecture… it’s such an “obvious” thing to use!

as far as roadmap is concerned… 2.5 with its “everything animatable” approach may overcome the colour thing… However, because of relative (ie based on particle age) vs absolute time and colour currently being “absolute only” it may not fix things… at first

Post 2.5 is the durian project which promises to look at FX and rendering… but that’s still a long way off.

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Just asked this from jahka (the particle system’s coder) and he said not in the close future since the code at the moment kinda lacks the possibility. It might be different in post 2.5 versions. You can create a tiled image with the frames of the animation in it though.

The split image’s frames can be randomized.

Some of it is possible with IPO’s. Check the new documentation: http://wiki.blender.org/index.php/Doc:Manual/Physics/Particles

You can do it either with a blend texture or with the split image mentioned already.

Same as above.

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You are forgetting to ask another question.

Can Billboard/Object/Group particles follow a path and align themselves to that path at all points as they travel along it?

No they can not.

What needs to happen with particles is Billboard, Group and Object need to be combined into a single particle type that can use the features of all. I mean, what is a billboard except a plane? And because you can not control the size of the Billboard, you end up with aspect ratio issues when you map Standard or HD footage to them.

Fixing the state of particles is simple.

1.) Make particles travel along a path and align themselves to the path as they travel along it.
2.) Allow groups to contain particle systems that parent correctly and don’t always end up at the origin on render (gag!).

With 1 & 2 implemented above, you could make a fleet of spaceships, each with its own exhaust system, traveling and aligning itself to the path.

That is my test for particle systems in any 3D package and most other 3D packages pass that test. Blender does not as of version 2.48a.

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I’ve been reading the docs and i’m confused about how to achieve this effect:

Have billboard particle system with each particle having a random image (for example, a square, circle or triangle), and at the same time, each particle fades in and fades out over it’s lifetime.

I’ve figured out how to do the first part (make a tiled image and use UV Split), but I don’t know how to combine that with a fade-in/fade-out ramp.

I realize particles don’t use “ramps”, but thats the effect im after.

I thought of maybe making a uv split texture where i have my random images laid out vertically in the texture, and have them alpha-fade along the horizontal. Then have the system randomly select which horizontal row to use for each particle, then the billboard would animate only horizontally over it’s lifetime (is this making any sense at all?).

But I don’t think such a setup is possible. Is there any way to do this?

EDIT: Oh, and I apologize for putting this in the wrong forum. It shouldn’t happen again. :slight_smile:

EDIT #2: I’ll start a new thread there now. :slight_smile:

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Please post this sort of stuff in the " composition visual fx and rendering"