Added HDRI lighting captured from filming location
To get realistic lighting and be able to match my render to the plate I used a HDRI that I captured on the filming location with a 360 camera from ORB, there was not much editing that needed to be done to this as the 360 cameras exported files were allready setup correctly, I just needed to tweak the values until the lighting looked and felt correct. I then added an area light that matched the real world location that the light would of been coming from to get some more defined shadows and specular highlights.
Creating materials for mycelium
I had quite a lot of trouble creating the materials for the mycelium. I wanted to have the displacement and colour change based on attribute values, such as having the colour and size of the mycelium corilate to the age of the animation so the larger parts would be a more darker / dryer colour and larger and the sub tendrils be smaller and have a greener more fresh colour. When creating the animation I allready had the values such as curveu that gets the length of the curve and perimeter, an attribute I created that controls the spawning of the smaller tendrils off the larger one. Converting these attributes from points to primitives and from the SOP workspace into the Solaris USD workspace had some issues but I was eventually able to access the values within the material editor and use them to influence the displacement noise and colour ramp.
Displacement maps
Lighting and test renders
Once I had the materials setup I make a basic lighting and render setup so I could render out 1 frame to test compositing in Nuke while I setup the final lighting and render settings and wait for the long render time.
In order to achive shadows on the wall behind the mycelium I used the wall mesh as a holdout, in Solaris there is a node that does this by routing in the render mesh then the shadow mesh and adds the shadows that would be appearing into an AOV channel on the rendered exr sequence.