Hello Community

I was wondering if any one has come across a method to create fire that is turbulent but more so transparent like this?

https://www.youtube.com/watch?v=GaspF7gW4tU [youtube.com]

Ive come across…something like it but am curious if anyone knows a better solution.

thanks

Hey there,

I made some fire something like this for a Nike commercial, see here:

https://www.youtube.com/watch?v=JMdwyIH9lSk&feature=youtu.be&t=18s [youtube.com]

I changed the pyro shader to ramp between red, green and blue for 3 different heat regions, and then developed the “transparent” look in 2D. Pretty much how I always use it now

Hope this helps

Ken

YES! thank you so much

how are you creating transparency in 2d though (i would imagine your using nuke) are you shuffling channels ?

Exactly right, just shuffle the channels (or separate r, g and b channels however your 2D app of choice does it) and you can treat them how you like. For instance perhaps you used red as the coolest region in the shader ramp, you could ignore the other channels, or adjust their color/opacity before comping them back together. Using an RGB ramp just makes it easier to separate and control in 2D as opposed to the default blackbody ramp.

kemijo
Exactly right, just shuffle the channels (or separate r, g and b channels however your 2D app of choice does it) and you can treat them how you like. For instance perhaps you used red as the coolest region in the shader ramp, you could ignore the other channels, or adjust their color/opacity before comping them back together. Using an RGB ramp just makes it easier to separate and control in 2D as opposed to the default blackbody ramp.

I'm not very good at compositing, but this sounds quite interesting. However, one thing I've never understood with rendering smoke/fire with RGB-colors is, how do you get the “right” color for the effect?

For example, if I just render it out like normal, I have my fire colored as fire. All good. If I however render it out as RGB, I won't have that fire color anywhere and I can't really use it as fire. Where do I get the fire color from? Are you re-coloring it in comp, or is this perhaps used as a pass - meaning I would have to render it out from Houdini 2 times, one RGB and one normal?

That is where I get stuck really. I can see the benefit of having a pass like this, but I'm confused in how to accomplish it. Is there a better way than having to render 2 times, or is that what people do?

You should always color correct your fx after youve rendered because lighting will only take you so far.

would you post a example of what your getting and a hip file?

You can do this look with the shader and you don't have to do any comp tricks. In the shader, instead using a linear curve for the emission, create ribbons of emission. Take a look at the attached screenshot.

Hope that helps,
Jason