There was a topic on Volumetric mats a while back, and I thought I'd revive it from a different angle. You see, I've been playing with fire. Forgive the pun. And I want to make a single flame. In this case, I'm in the process of making a small blow torch flame. In the picture, there are two flames. Both are identical except that one is grouped. Why do all the mats from interior objects take on the properties of the exterior mat when they are grouped? Why oh why? More importantly is because I plan to boolean, and this will not work. Bad Bryce. Bad, bad Bryce. The flame is made with 3 cones, each with a different volumetric material. It's a little frustrating, so I'd appreciate any insight.

Ooops: That one sentence is meant to read "More importantly is there a work around because I plan to boolean."

Have you tried making separate groups of positive and negative cones for each of the three? Sorry, for the outer two. It would be like this, going from the outside: 1 positive 2 negative copy of 2 positive 3 negative copy of 3 positive And then grouping the groups together. I cannot try, because I have a picture rendering, but I'd really like to know whether it works. It's just something that popped in my head.

I'll admit, I'm confused, but I'll try what I think you mean.

I have a theory, but didn't try it to find out. When you put the three cones inside one another and render, a blend is reached and you get just that, a blend. When you group, the dominant material is the outer skin. To group and still have the illusion of a blend, you'll have to decentralize the cones so that each has surface area unobscured by the others. In other words, instead of one inside another, put one on the edge of another. .... adendum, after trying this, it didn't work so great. Playing with transparency helped more. Might have to increase the transparency when overlaid. Of course, I was not playing with volumes, but rather, regular textures. hmmm, good luck and send me a post card.

I'll try explaining again step by step, though I don't have Bryce here and forgot last night. Create the outmost cone. It's Cone 1. Make it positive, duplicate and make the copy smaller and negative. Group together so you get a hollow cone. Duplicate the inner cone, ctrl-x and ctrl-v it, so it's separated from the first group. It's Copy of 2. Make it positive and a little smaller than the hollow in the first cone. Repeat the process from the first group, so you get a second hollow cone. Take the negative from the second group, cut and paste it, make positive and again a little smaller than the hollow of the second cone. Apply separate volumetric materials to each group. I think that the trick with making each group smaller should work. It is possible that you'll lose the textures if you group the groups to position them. So simply ungroup them when you put them in the position you want. HTW

It seems this would be a theory topic, since none of you apparently have Bryce available to try it out on! Goddamn inneficiency, but the flow of ideas is good. Instead, I'll answer your question, Johnpenn. I've myself run into some gnarly volumetric problems in Bryce using booleans. It's because in Bryce, there ARE no booleans. When you group objects together, Bryce doesn't create any real geometry like we all originally hoped. Bryce uses a filter process similar to what you wuld do manually in Photoshop to create objects and whatnot, and THAT is why it doesn't work on volumetric materials. The problem doesn't lie in Bryce's internal programming, rather in the fact that volumetric matrials have VOLUME. So, the Density, Fuzziness, and Edge Softness play a huge part in how your render will work. If you're animating, I suggest trying a regular procedural approach. If you're doing stills, then honestly sir there's no reason why you need to group ANY of these objects. You're playing with FIRE, not matter. Fire is photons, so you should focus on light-sensitive materials as opposed to regular volumetrics. If I seem abrasive, I apologize. But last time I checked, you couldn't grab or hold fire. Unless you're a DRAGON (grins).

Or unless you're a fire-dwarf. :-) Ordinary textures might work, if you play with transparency as Eric suggested.

Uhm... yeah. Anyway, I tried Erlik's ideas, and I got different results. It's still not right, but it's different. I figured how to a boolean that's good enough by using intersection instead of positive/negative, but I have to wonder why is that when 2 volumetrics overlap you get such unpredictable results? Anyway, here's the latest pic. The left flame is 2 groups which are shown individually on the right. I'll keep tinkering, but I welcome any more ideas.

Oh yeah, check out when the 2 groups are arranged cocentrically that the outer cone gets a more solid, sharper edge. How's that for wierd?

Johnpenn, talking about volumetrics. Take a look at my Gallery of recent days, and look at the volumetric CLOUDS. Talk about a lot of work and RENDER TIME, some of them took 17 hours. The one called Summer Sights used the most time. This MIGHT help in understanding Volumetric problems, eventho yours is fire. Did you try making the Mats negative in the Material Editor? Sometimes awesome results. As a sidenote: I have another pic. called Anti-Matter Genisis or something. It used 4 seperate volumetric materials. This might help to visually look at RESULTS and not necessarily words to help you understand. May you succeed at your goal. Lightpen