sometimes in vfx world you need volume rays in a shot. it could really difficult to render this in 3d application like maya or houdini. there fast and easy to use volume rays in nuke. with few tricks you can make them work in stereo.
first you have to do, render white retangle in 3d app with your shot camera. in nuke you can track for each eye (left and right) the corner of the retangle. this way you get a perfect motion path.
with ctrl-click you connect the tracker information to left and right center transform of the “volume ray” node. this will give correct stereo volume rays.
using inverted mask from correct rendered character / forground elements —> the volume ray node give good stereo holdouts.
if use noise node in nuke to feed you feed volume rays. you connect the tracker-node to tranform-settings of you noise. it will give a stereo approved noise. you can animate the noise in nuke, this will give almost realtime feedback volume ray animation. see example movie.
its much faster way to work, if you need simple go rays.
its simple test for mud and snowtrails. i trying to recreate to old “renderman-deepopacity-displacement trick”.
instead of using a displacement shader with craps depth-information from a light. i rendering sperate passes and use nuke with timeecho node and expressions to create a animated displacement maps for the trails.
p style=”text-align:center;”>i am trying to create with python a one-renderpass workflow like with the smart rendermanshader setup in maya
p style=”text-align:center;”>the displacment map out of nuke
for research i´ve made a research for generating 3d-tree´s in a compostingsoftware like nuke. i have compine classic game-3d-multiplane with nuke 3d-displacements nodes and for tree wind motion i had used a default grid wrap node.
now i can build my “forest”-gizmo for easily generate a 3d-forest/tree “on the fly” in 3d compositings including a soft fake-trees-shadow and fast relighting/shading feature. the rendertime are not so good (3-4 sec per frame in PAL) i´ll want export the data to maya and renderman how can render the tree pass faster and more features like deep shadows.
finally, i had finished sets of the nodes in nuke for my waterfalls. i can change the look of the waterfalls in realtime and place it in the 3d space in nuke. so i can fly around in 3d-space and place so many waterfalls i want… the rendertime takes about 5 seconds in nuke (incl. displacments) with this different waterrfalls. (all created with same base-layer).
p style=”text-align:center;”>here is a little test…. the waterfall rendered by my toolbox in maya as texture and projected and displaced in nuke on a plane… it works for a couple of shots….. fast and easy…. good base for 3d matte paintings… for the closer shots into the waterfall i´ll need detail rendering direct out of maya and renderman