REVIEW: Redshift 2.6 for Houdini
A look at the latest update of the renderer
Nowadays almost every company who originally worked on developing a CPU renderer has a GPU version in the works, but most of them are not released yet or are not matured to use for VFX production. The advantage of Redshift is that it is purely GPU based with many years of development behind it. Additionally from a Houdini user’s perspective it is the only tightly integrated and production proven GPU renderer on the market. As is normally the case in the realm of successful renderers, Redshift has been through every step of the ladder, starting in the product visualisation industry, followed by architecture, indies, then adverts and VFX for TV. But recently we can see more and more Redshift-rendered sequences on the big screen. For example Hydraulx adopted Redshift in their pipeline, starting with the Rampage movie. For those who are interested in the details, there is an article on the
The first impression of Redshift for a Houdini user, who would have used Mantra before, can be described as a similar experience to driving a Tesla electric car for the first time with the so-called ‘Ludicrous’ acceleration mode. The extreme performance gain makes deadlines more achievable with frequent iterations, especially with the two denoiser options released in version 2.6: Optix and Altus. The first is free, but Altus needs an additional licence, which is discounted for Redshift customers. Both of the denoisers seem to be a working solution for the never fully dampening GPU noise. This is the most obvious disadvantage of any Gpu-based renderer because the computation isn’t always as precise as with CPU renderers. Usually we get a pretty decent image for look-dev in few seconds, but for a final render it’s hard to get rid of the noise.
Recent releases of Redshift received many other useful features like multi-step motion blur, Cryptomatte support and post FX. The latter has quite a rich feature set, which doesn’t just help to quickly achieve good results without comp, but can also deliver more convenient feedback for look-dev.
Redshift works in all the native Houdini render outputs (Render View, Mplay, viewport overlay, file output) but has also a custom render view, which is more responsive and has additional features like the switch between progressive and bucket rendering, denoiser button, and colour management settings.
Of course Redshift isn’t as integrated as Mantra but supports, for example, Material Style Sheets which aren’t usually found with other third-party renderers. Instancing also works well with both the Instance OBJ node and with the Instance point attribute. We can also use native particle rendering which instances a sphere on every geometry point and the only limit is the system memory. Redshift has this out-of-core feature for other geometries and textures as well, so the weakest side of GPU rendering isn’t a big issue with Redshift and in those cases, it is still faster than with a Cpu-only renderer.
Just like other third-party renderers for Houdini, there is a container material node for the Redshift shading nodes. We can access all the nodes there, of which there are quite a few. For those familiar with physically based shading, it’s easy to build proper networks. The material nodes are not just fast shaders but mostly physically correct. The volumetric shader is a bit weak as there is no phase function and texture inputs, but there is a global one in the ROP node to simulate fog with better shading capabilities.
Redshift isn’t bug free but with updates rolling out frequently with the developers being keen to see feedback they usually fix them in a short period of time. The community is good and helpful, there are many enthusiastic users on the official forum, some with multi-year experiences.
Redshift has many years of development behind it