Simulating with Voxels


the goal of this project was to find a way to melt a lot of different objects.colors and materials had to melt too.Initial tests in the studio with houdini particle fluids proved to be the way to go.

it was my first time using particles and dops in houdini.

nevertheless , I decided to have a go with the voxel solvers in houdini to see if similar effects could be achieved.

i spent some time playing with solvers and finally after some struggles with the liquid solver I decided to continue with the sand solver as a base and try to build my stuffs around it.

struggling with the liquid solver:

first i had to inject keyframed animation (velocities) inside the simulation.this was done by blending custom velocity fields inside the simulation with simple y ramps.


the bottom of the shape (the drip ?) was controlled via painted attributes on the surface of the object controlling a mix of tangential and normal forces that would “sculpt” the final surface.



while simulating , the original polygon object was advected in the velocity field and a fluid surface object was created from the advected sand point cloud.


the result of the simulation was used as an obstacle for an additional particle fluid simulation from painted area.


finally I built a simple solver that would mix both velocity of the sand and sph simulations.a lot of points (2 millions) are then scattered on the modelled object and readvected within the final velocities.


uvs are transfered and carefully preserved all along the process.we also advected a material tag that would give us the possibility to blend between different materials.


the final rendering was done with mentalray in xsi . it was quite hard to render refraction correctly from the fluid surface but it seems to be a mental ray problem.finaly more filtering while generating the surface did the trick.


another shot I did :

you can see the final commercial here , directed by FredericPlanchon

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