Iridescence on surfaces is an interesting effect and can be a challenge to get looking correctly. This effect occurs for example on some animal skin as well as on surfaces covered in oil under certain conditions. Because it is a very specific look it can often times require lots of iterations until the client is happy with the result, so quick turnarounds are often neccessery. Luckily it also often times is quite a subtle effect so it’s a good candidate to try and look develop in 2D instead of constantly re-rendering your CG.
The new RIS mode introduced in RenderMan 19 is a completely new render-engine that is very different from REYES. Being a brute force path tracer (uni- and bidirectional modes) it works much more like other renderers that follow a similar approach (e.g. Arnold). That approach aims to make the render process more simple and interactive. And while I personally don’t like it completely yet it seems to get widely adopted in the film industry and we all have to adjust to it sooner or later :)
In the process of trying to streamline things a bit more in my day-to-day workflow I have recently been working on a hand-full of small helper tools. One of them is a small set of scripts that handle the conversion of a selection of files to Arnold & RenderMan’s native .tx/.tex files from the filebrowser… because people like the GUI, right? :)
One of the great things about Katana is the ability to have a simple compositor right within your lighting/lookdev environment. I have been using its 2D features more or less extensively throughout the last couple of projects. It’s quite handy to tweak your HDR that you’re using right before you plug it into an environment light, without the need to go into Nuke again if you’re doing just smaller tweaks. Unfortunately Katana’s 2D interface lacks quite a few things that would make it a valueable alternative to Nuke for preparation tasks, because you have to wire more things together. So I was working on a few ‘gizmos’ to make the process a bit less cumbersome.
Integrating CG into uneven soil is an interesting challenge. On a recent show we had to integrate CG characters into plates which often had a grassy ground. For Comp it’s benefitial if you get masks from Rendering to aid the blending of the CG elements into the grass. If the ground the characters are walking on is flat this can easily be achieved with a standard PWorld AOV. It get’s a bit trickier though if the characters are walking up a hill or a similarly uneven surface, because the coordinates at which the character comes in contact with the ground are constantly changing. I’ve been trying to come up with a system to make a Comper’s life easier and found a relatively simple solution.
Image based lighting often times simplifies getting started with a good lighting setup when trying to integrate CG into life action. Often times it’s beneficial to have the IBL sphere to just contain the ambient lights from the environment and therefore to paint out any actual light sources from the set. Those can then be used on separate lights to give the main illumination from the set lights, while the IBL sphere contributes ambient environment light. Now, if you have a lot of different environments and consequently a lot of different HDR’s it can be tedious to paint out the lights and output them after that…