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You are here: Homepage /  Tutorials & Tips /  Tutorials / Vray Animation Optimisation
Vray Animation Optimisation
 
 
Posted: Mar 02, 2012
Published by: the area
Homepage: Visit the page
Software: Autodesk 3ds Max, Autodesk Maya, Autodesk Softimage
Category: General, Rendering
Skill: Intermediate
 
Tutorial Steps
1Displacement
2Antialiasing filter
3Glossy reflections
4Reflection/refraction depth
5Global illumination
6Calculating GI
7Excluding objects
8Subdivisions
9Managing available memory
10About MintViz
 

Rendering animations using Vray can undoubtedly leave you in frustration when it comes to render times. The high gloss materials, reflections and displacements that you use for still images can make your total animation rendering time beyond manageable.

Here is a compiled list of tips and tricks to help keep those render times down but still keep a high standard of quality and there will be more to add soon. If you think you have any useful suggestions that you wish to share, you can leave them in a comment below or email them to us.

Displacement

Using displacement in still images is a slow process. When it comes to animation this process becomes far more complex and usually involves careful planning, especially if you need to keep that carpet looking like carpet.

tip Tip

For areas such as grass and carpet, use 3d mapping. The textures for the 2d mapping will need to be loaded for each frame and if the texture maps are large this will take some time. For carpet and grass, the edge length for 3d mapping can be set quite high and still look good. The lower the edge length, the more Vray subdivides the mesh and this increases the render times. Edge length is resolution dependant, the higher the resolution, the higher this value should be. You should also make sure that the view dependent option is enabled. This can reduce flickering due to the quality of the displacement being spread much more evenly.

Antialiasing filter

In order to keep the render times low, you usually sacrifice the quality of your subdivisions for lights and materials which in turn introduces noise.

tip Tip

By using sharpening filters such as Mitchell-Netravali you are introducing more noise into the render on top of the noise already created via the low subdivisions for lights and materials. Try to use blurring filters such as area instead. It will generate less noise and help blur out the noise that already exists.

Glossy reflections

The biggest slowdown of all is glossy reflections within your materials. There is no escaping using them if you want your materials to look realistic.

tip Tip

Keep the glossy reflection range between 0.7 and 1 and adjust the subdivisions accordingly. Chances are that within a animation lower glossy values will go un-noticed. If the result is satisfactory you can use light cache for glossy rays and then the calculations for glossy reflections will be much faster.

Reflection/refraction depth

Surrounding objects are important for reflections and refractions. The max depth determines how much of these surrounding objects are used within the calculation.

tip Tip

Lower your max depth values to 3 or 4. When a reflection or refraction can no longer be traced it will look to the exit colour. You would set the exit colour to a similar colour to the material that it is reflecting and/or refracting. You can control this individually for each material or in the global settings.

Global illumination

Vray slows down as more objects are introduced into the scene that are contributing to GI.

tip Tip

For objects such as trees in the background, exclude them from receiving and generating global illumination and shadows.

Calculating GI

Not everything has to be on during the pre-calculation of the GI.

tip Tip

Displacement can be turned off when pre-calculating the irradiance map and light cache. Turn it on when you do the final render.

Excluding objects

You may have areas within a scene that are not visible in the first few frames but are visible later on. Leaving these objects visible for the whole animation will certainly keep your render times high.

tip Tip

Plan your scene, use layers and group them accordingly. If there is an upper floor of a building that does not come into view whilst on the lower floor hide it completely. The chances of it contributing the reflections and/or refractions of the lower floor are small. Break the animation up in to small sequences and use multiple cameras.

Subdivisions

Shadows and glossy materials are controlled by subdivisions. A low subdivision gives higher noise and a high subdivision leads to longer the render times.

tip Tip

For animation, subdivisions can be lower than they would be for still images. There is much more going on in the scene, i.e. moving object’s and cameras. A little extra noise will go un-noticed.

Managing available memory

Large complex scenes require a lot of system memory to store all the information for rendering.

tip Tip

By using Vray proxies you will free up memory for other calculations. If you stay within the memory limit you won’t actually speed up rendering by using proxies. Once the memory has been used up, 3ds Max and Vray will start to use the system page file. This is when the rendering starts to slow down.

Vray uses dynamic memory and static memory to calculate various processes. These two processes can play against each other over the available system memory.

tip Tip

Processes such as displacement use dynamic memory. For heavy scenes that have displacement you can increase the dynamic memory limit to help the rendering process. Increase the default value to around half your available system RAM, memory must be kept free for other processes. Keep in mind that by increasing the dynamic memory limit you are reducing the amount available for the static memory.

About MintViz

James Cutler is a 3D Digital Designer and founder of MintViz, a creative consultancy that provides tutorials, tips and resources for the CG industry.

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Newest users comments View All 8 Comments
Posted by anzyu on Sep 06, 2013 at 07:57 AM
Very practical tips!!!!!!
Posted by Big fish on Aug 14, 2012 at 09:54 PM
Thanks for sharing.
Posted by 3abdelhakim on Apr 19, 2012 at 02:27 AM
thank you from the heart
Posted by aboumaryem on Apr 05, 2012 at 11:58 PM
Thanks for sharing ideas with us..!
Posted by Anthony on Mar 23, 2012 at 05:22 PM
tanx yoo