Octane Scene Optimization

VRAM is probably one of the single most important considerations when using OctaneRender®, since VRAM determines what you can actually get done in any given shot — if your scene or parts of it doesn’t fit into VRAM it is not going to render. Out of Core is useful to address VRAM overflow, but it can only go so far, and performance will suffer. So many scenes come into Otoy Tech Support that are not using VRAM effectively. This guide will offer suggestions to help you create scenes are optimized for Octane.

Here are the highlights covered by this guide:

  • Layers
  • Naming
  • Instances
  • Duplicate Materials
  • Octane Materials
  • Octane Object Tag
  • Map Type

LAYERS

Always break your scene down into layers In Cinema 4D. This way, you can keep your Object Manager organized and easily control what is displayed at any given time. Layers can work hand-in-hand with the Solo function in Cinema, but using Solo is more cumbersome when it comes to look development and lighting. Layers instead offers the ability to solo whole layers, including layers that contain scene lighting. Layers will also help to isolate aspects of a scene that may be having issues, or, worse, causing crashes (whether Cinema, Octane, or some other plugin).

NAMING

Name everything. Doing so helps keep the scene easy to read and organize. Naming is also a great help with xpresso and works well for tracking down errors.

REDUCE THE USE OF CINEMA MATERIALS WHEN POSSIBLE

Cinema materials need to be converted by Octane on the fly, and that conversion takes time — in some cases, much time. The conversion occurs and is then loaded onto your GPU card every single frame. Fortunately, Octane can convert these materials into Octane format on demand, by opening the Live Viewer and choosing Materials > Convert materials in the Live Viewer menu bar.

ORGANIZE YOUR SCENE

Scene complexity will often hide opportunities for optimization — sometimes, you cannot see the forest for the trees. The best way to manage complexity is to organize your scene into logical chunks. Use the Layers panel in Cinema to organize scene elements however you wish. By putting scene items into their own layers, it is easy to focus one on thing at a time and solve one issue at a time.

ISOLATE ELEMENTS FOR SIMPLICITY

In addition to the Cinema 4D Layers panel, there is a tool called Viewport Solo which has two options, single and hierarchy. The Solo function will hide everything else in the scene, allowing you to focus only on what has been selected at the time the tool as pressed. The layer system is superior to solo, as layers can also be solo’d, but there are times where the Viewport solo does the job needed. It is a nice complement to layers.

USE INSTANCES INSTEAD OF DUPLICATES

If you need to have multiple copies of the same thing in your scene, use the Instance generator in Cinema 4D. In the case of a cloner, choose the Render Instance option. The VRAM savings will become more apparent as you have more instances in your scene. You will hardly see that Used Memory value climb. However, if you had plain copies, you would see the User Memory value climb. You can check this yourself by using a cloner and switching between Instance and Render Instance values. Render Instance will always be lower.

USE THE OCTANE OBJECT TAG

Always apply an Octane Object tag to your scene objects. This tag will give you options that Cinema cannot do as efficiently, such as using subdivision to smooth your objects at render time. Doing so is better than using the built in Cinema 4D SubD generator, as the file transferred to the GPU will be much lighter in polycount and transfer more quickly.

USE OCTANE-FORMAT MATERIALS

Materials should be in Octane format for the best results. If you have multiple materials in your scene, they should be unique. Duplicate materials will take up twice the space in VRAM. If you must have copies of objects with the same materials (that cannot be instanced, for some reason), then make sure that you use only one material applied to those copies. You can check to see if you have done this correctly by checking the assign tab on the material. You should see multiple entries, one for each character that uses that same material.

SET THE PROPER IMAGE MAP TYPE

Make sure to properly set the Map type of each Image Texture correctly. The auto function will try to guess, but for grayscale or alpha images, it’s best to set the Map type value specifically — this way, only the VRAM actually needed for that image is allocated, as opposed to more. If VRAM is allocated, but not used, it is just wasted.