Over the next weeks, I focused on my tasks, such as the creation of Portals for Scenes 2,4 and 5, comping one of them into the shots for scene 2, and lamp clean-up from shot 6.
I started off with the hardest one, specifically for shots 3 and 4. Firstly I just experimented in Houdini and got the following results:
However I wasn’t happy with the overall movement and I wanted for it to have more control and flow from inside to the outside whilst being attracted to a central shape inside. So, after finding a great tutorial (https://www.youtube.com/watch?v=SnGSCO0CwAc) I re-made it into a different shape. I also added a light source, trying to imitate the lighting in the scene and created a rough geometry to represent the wall, floor and the sidewalk, such that the portal and smoke coming from it could interact with these.
Portal node graph POP network DOP network
Viewport Geometry set-up node graph
I then made a simple set-up for compositing in Nuke of the rendered out versions of portals to get feedback from the group.
I also added an image of a different location to be seen through the portal and started to figure out how to add distortion or warp effect to that image. After a couple trials including creating a Heat Wave effect with the use of nodes ‘Noise’ and ‘IDistort’, I realized that having a sequence of popular locations would be a better choice to see a more natural look. For further work on compositing the shot and achieving the final vision, I need to implement some ambient lighting, dust flying around, and put some distortion to space before the portal appears.
For the division of the workload I was assigned to a partial clean-up in shot 6, of the lamp to be exact. Proceeding with simple rotoscope, rotopaint and subtle adjustments with the use of Blur, EdgeBlur or Erode I cleaned out the lamp fairly quickly.
I then proceeded to make the second portal, which we decided to be of the fire shape. As a starting point, I used the Houdini script I made for the first trial of the previous portal. I then adjusted for it to be on the floor, to follow the shape of a circle from the shot and animated its appearance. The next step was to create particles and figure out the way they would be simulated in a POP network. After the look was finalized any particles below the floor level were excluded from simulation and volume was create with attributes of density, temperature, and velocity. Finally, the smoke was solved with the use of PyroSolver inside the ‘DOP network’ and later read into the main script with the use of ‘DOP Import Fields’ and converted into the VDBs. Furthermore, I added material to the fire and created a Mantra Renderer.
Fire Portal Houdini Network POP Network DOP Network
After feedback from the group, I will adjust the portal’s animation if needed, set up the lights, set-up floor geometry for shadows and change the renderer to be Arnold and set up Arnold materials for the objects. It will also be important to find the precise number of frames such that I could animate it correctly.