Fume FX assistance?

#1

Hey all,
Been a while since I’ve used Fume and am wanting to create a fire trail. Easier to show than to explain, try this link: http://www.youtube.com/watch?v=Ox_LnaI3oWo

As in the video, I want it to grow from one end to another. I figure using an animated texture to control that part. Mostly I’m curious on how to get it to fan out like in the clip while burning out the top of it. One idea I had was just a color gradient for the look, but how to get that secondary flame to emit is a big question for me. Any and all suggestions would be awesome.

Thanks.

#2

Most convenient setup would be with particles. You’ll need to adjust the look precisely with the gradients, but the motion shouldn’t be that hard - drop down pflow particles from a moving source, and put a wind to fan it to the side.

#3

Yes, yes… that had crossed my mind. I will give it a go. Thanks for the tip! Love your work, by the way.

#4

I can’t seem to dial in the gradient as I’d like. Does it work from the inside out? I can’t get it to be blueish around the edges. Do I just have to live with that?

#5

The way it works is based on density - one end is the core and the other is the periphery. Try fiddling with both the color gradient and opacity AFC, you should get a feel for it :slight_smile:

#6

Here is a test render www.freespiritfilms.com/videos/fume_test.mov. I know it has a long way to go flame wise, but I’m pretty close to where I wanted to be with how it flows out initially. Let me know what you think.

#7

Going well, now you gotta increase the resolution!

#8

Hmm, the spacing is already at .25, but I’m going to try and go lower. Aside from that, what else would increase the res?

#9

The res IS the spacing, more precisely - the size of the voxel in screen space. Make sure your FFX box fits as closely on the effect as possible, and then turn the spacing down :slight_smile: When you do that, you will also need to decrease the particle radius, if you are using particle source, so it stays at a little above voxel size, and increase the number of particles so you don’t get empty areas.

#10

Yep, that’s what I thought. After a bunch of testing yesterday, I figured all that out. The main thing that I realized was causing so many problems was that my fume box (and the whole scene) was way too small. It would stop simulating less than 1/3 of the way through and the res wasn’t getting any better. As soon as I made the scene larger, it would simulate through (albeit very slowly after I adjusted the spacing to match, which is fine).

I’m hoping to post something else tomorrow as far as an update. I think it’s looking better, but with all the new info, I’ll have to go back in and re-sim it.

Thanks so much for all your help so far! Quick question, though:
The turbulence noise scale. Will a lower # give me “tighter” noise? Silly question.

Thanks!

#11

Best way to get a feel for it is to experiment, do so aplenty. Smaller scale gives you smaller whirls.

#12

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.