Shot 3 Full Render Preview
We've got paws again ladies and gentlemen! This absolutely GINORMOUS lynx isn't stopping until he's turned that city to dust, one block at a time! This shot took a LOT of simulations to complete and I had to re-render 3 times to get the result you see below. I hope you all like it!
Pyro Tips and Tricks
A lot of my previous WIPs have focused on how to set up a pyro simulation in general, but I want to break down some of the tips I've learned while working with Houdini's pyro solver over the past year!
How 2 Visualize Your Volume Attributes
If you've worked with the pyro solver before, you've probably came across a problem with one of your volume attributes. Typically you have density, velocity, temperature, and burn. I typically use the former two, that being density and velocity (v). Visualizing your attributes is a great step to figuring out where something went wrong.
You can find this option under the "fields" tab in the pyro solver.
MICROsolvers
Yes, you read that correctly. Houdini has microsolvers! In the pyro solver, Houdini will give you options for various fields such as disturbance, turbulence, shredding, etc. However, these are all technically internal "microsolvers" that aid to the overall simulation by injecting different types of velocity.
You can access these microsolvers by diving into the pyro solver. Microsolvers are a pretty complex subject and you can watch a VERY in depth tutorial here!
Pyro Burst Source on Points
Using pyro burst source is a great way to get a quick explosion or shockwave... but what if you wanted a SERIES of explosions? You can actually use a series of points to accomplish this!
You can accomplish this effect by first plugging points into the input of your "pyro burst source" node. Then, in the burst animation tab, you can click the little dice icon to generate an attribute randomize node. This will allow you to control the initial start frame and the length of how many frames it will take for all explosions to occur through an attribute adjust float node.
Normalizing Vectors for Velocity
This is a bit more technical. In shot 3, I needed to create multiple impact points for Legacy's paw as they hit the ground at different times. This means that each source had to have a different velocity that pushes out from the center of the paw. We can do that by "normalizing" values.
When you "normalize" a vector you are essentially averaging the magnitudes of every vector into their unit vector forms. This means that each vector will have a magnitude of 1. We can use that to our advantage as if we normalize each vector based on its position in space, we'll get each vector's unit vector. However, this isn't what we want. We still need to determine a center for our vector to normalize around.
By dropping in an "add" node, I can create a point in space to use as the center. I can then retrieve the positional data of that point using the code seen above on line 1. Subtract that from each points position and you can now push the smoke away from a center value.
Risky Rendering
Blender 5.2 is currently in alpha, but that won't stop me from rendering in it! 5.2 adds a new feature that I've been desiring for a very, very long time: texture caching! This option enables Blender to export "tx" files, which hold adaptive resolution data.
This SIGNIFICANTLY reduces RAM consumption as Blender will employ a technique called "mipmapping". This adaptively reduces texture size based on the resolution of your image and will only load the necessary resolutions into memory.
This saves me TONS of rendering time and also allows for me to put a lot more into a render. Of course because 5.2 is an alpha build, there are bugs I have to work around. Overall the experience has been good and it's the whole reason I was able to render shot 3 at all!
Shot 4 R&D
I've already started working on shot 4. I've wanted to try doing some simulations for missile or tank shell impacts and now is my chance! Using the pyro burst source method I talked about earlier in the WIP, I concocted this test sim that follows Legacy's body movements. I want to add trailing as well for the missiles or shelling but that will come later.
I've also been working on the scale and lighting for shot 4. No animation has been done just yet but I have a general idea of what I want the next shot to look like.