Trying to understand how this lava after was done

[houdiniMAN]

hi all

 

 

     The more i look at this effect the better it gets, but I'm have problems understand how to control the viscosity with temperature to the level seen in the video I have been told it looks like it was done in vex (vex isn't my strong suit) I would like a better explanation of the process it took to get such go control of lava (flip fluid). 

 

thank you

 

 

 

http://vimeo.com/97108317

Edited June 5, 2014 by houdiniMAN

[Solitude]

Basically you just tell the temperature attribute to cool down over time (subtract or multiply down over time until it reaches a certain threshold). Viscosity just increases as temperature decreases... likely being remapped to it's own range of values.  I've attached a basic scene file.  Ideally you could also use surface to cool it off from the outside in with a bit of noise, and also use temp to drive displacement in the shader...

simpleLava.hip

[gramx]

Link to hip file for my test lava shader is now in the description area on Vimeo. Its the first time I have played around with Mantra shaders so it might be a bit messy, but it works!

[houdiniMAN]

wow thanks  solitude, and gramx

 

  The question I still have is how do I control(set) the temperature. It's cooling to quickly for me( in solitude file). What i'm trying to say is, because viscosity is based off the temperature how do I control how the temperature cools( giving it custom values). For example gramxs video shows that at the hottest level the viscosity is 25 and at the coolest its 100,000. How do I get that level of control, and is there way to control how long the temperature stays hot and when it starts to cool.

 

Thanks for the help guys 

Edited June 5, 2014 by houdiniMAN

[gramx]

You should be able to just decrease the amount you are subtracting from the temperature each frame. You the map this to Viscosity with a fit range. It takes quite a few test simulations before you get a good value.

[Solitude]

Thx for posting up your hip Graham. The end result looks great, so it's ok if the shops are a little messy.  

 

In my file the temperature decay is done on the gas linear combination dop, and the viscosity remapping is done on the geometry vop. 

[olivetty]

Basically you just tell the temperature attribute to cool down over time (subtract or multiply down over time until it reaches a certain threshold). Viscosity just increases as temperature decreases... likely being remapped to it's own range of values.  I've attached a basic scene file.  Ideally you could also use surface to cool it off from the outside in with a bit of noise, and also use temp to drive displacement in the shader...

 

Sorry for reviving an old thread, but that last part, about driving discp with my temp attrib, how the hell do I merge the two attribs together so that it affects both disp and emitcolor? Right now I have a surface cache node in the particle_fluid geometry node which feeds into to different nodes (color1 which is just a rampcolor from an attrib = temp) and I pass that out to attrib rename and rename it from Cd to emitcolor and put that into an attribcopy together with the surface cache (this is the lava shelf tool of setting things up in H15).

 

How do I create infinite attributes affected by temp which all feed into my null at the end (drive basecolor with temp, displace amount with temp etc)?

[Solitude]

You need to do that in the shader itself.  In shops, you would put down a bind node, set it to temp attribute from the mesh, and pipe that bind node into a fit range for displacement, and then a separate one that you pipe into the emission intensity, etc.  You can multiply the existing values as well with these new nodes... etc... many options are available here. 

[Farmfield]

Aach, don't listen to Graham, his RnD on this is shoddy at best...