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kyle890229

Week 6 Refine Portal & Add Light Streak Effect



What I have done this week:

  • Create light streak effects.

  • Add more layers and variations to the portal.

  • Add variation in color, so it does not look flat.

  • Create Disk Matte for Compositing.

  • Setup Houdini Render Pipeline.

  • Adjust portal angle in shot 2.

Goals for next week:

  • Keep refining portal and light streak effects.

  • Create different render layers for compositing.

  • Resolve the particulate issue, but still retain information at the outside of the portal for heat distortion.



Here is a new slap comp of the new portal in Shot2. I move it forward to the right place.



Since our team was still working on our commercial, we didn't get a chance to show the mentors and get some feedbacks. However, we still made a lot of progress and I also made some changes to the portal. The first thing I added this week is the light streaks effects. This was originally in our Pre-Vis, but I didn't know how to make that at the time. Now, I am more familiar with how the particle simulation works. I was able to make it work, and here is how I made it, although it still needs more work.


I create separate smoke simulation with a wind force when the motorcycle passing through the portal, so I get the smoke to float back. I also add turbulence, so everything is not just going directly straight down the road.



After the smoke is cached, I used it as advection for the popnet. It didn't work at first when I plug in the smoke. The particles were only being affected by it a little bit. Therefore, I add a popattract to attract the particles to the right direction, and it also gives me control of how fast I want the particles to shoot down the road. Finally, I used velocity as the attribute for the color.



While experimenting, I used the same simulation but I change the smoke advection type from update force to update velocity to create a different look.



I also saw Jie's blog, who from team Future, of how he randomize the scale of the particles, so I implemented similar idea to mine to create some variation in point scale.



Another big thing that has been changed is the pipeline. We have change all the render of the FX from Arnold in Maya to Mantra in Houdini. Special thanks to Nate for helping me setting up render layers in Houdini. By attaching mantra nodes together, I can now render different render layers on the render farm.



Candidate Objects is the objects that is going to be seen, Forced Matte is the object that is going to be blocking the candidate objects, and Exclude Objects are all the other objects that I don't want in the render. That's why I use * for all objects, and ^ to exclude the candidate and forced matte objects.



Since the FX is the only thing being rendered in Houdini, the render of the motorcycle will not have the light reflection from the portal. Consequently, we have to create a render pass to for Mich to comp in the reflection. We follow Jie's method that he used in his team. We apply a black mirror material to the motorcycle. Therefore, the only thing visible is the reflection from the portal, and Mich, our compositor can use it to merge onto the motorcycle render.



I had also created two new matte to help the compositing process. The first one is a matte for the inside of portal which allows Mich to composite in side of the portal. I used the same rectangle plane and boolean it with the portal emitter shape after the mountain node. The issue with this method is that the particles are being emitted from a 3D shape, but the matte is flat. Therefore, sometimes the edge will be smaller then the shape of the portal, and Mich will have to extend out the edge to fill the gaps.



The second matte that I create is a disk matte. The middle is white and gets darker closer to the edge. This matte is being use to help composite the reflection on the ground, so the reflection on ground has a gradient not just a reflection. I made it by attribute transfer white color attribute from a sphere to the black circle.




SPECIAL SHOUT OUT TO MY TEAMMATE FOR AMAZING PROGRESS THIS WEEK


Goal for next week:

  • Adjust the portal base on the mentors' feedbacks.

  • Resolve the particulate, but still retain information at the outside of the portal for heat distortion.

  • Maybe separate the particle layers for compositing

  • Keep refine the portal and light streak FX.

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