- This lesson will take you through using V-Ray RT in different ways
- The information centers around rendering and visualizing changes in a scene using RT
- This lesson topic is approximately 15 minutes in length
- Lesson covers all 3 Learning Cycles for the Lesson Topic – Lecture, Demonstration, and Activity
Goal - This lesson will give you a general understanding of V-Ray RT and its capabilities and limitations when running on CPUs and GPUs. Additionally you'll be able to optimize the performance of V-Ray RT and set it up to create final renders of single images and animations.
Objective – We will render a scene using RT in a few different ways to get an understanding of when to use RT for your workflow.
Outcome – You will be able to efficiently render in near-real time to assess changes and edits in your scene as you make them.
To set up the lesson follow the links below and download all available materials:
- CPU vs GPU Rendering
- CPU renders on main processor
- GPU renders on the video card
- Progressive Rendering
- Starts rendering the final image quickly for faster feedback – computes the whole image at once, instead of in stages
- Noisy at first, but the system continually refines the render until stopped
- Easy to setup, only a few controls to adjust
- V-Ray’s RT is progressive
- Interactive Rendering
- Allows you to edit and adjust your scene while the render is updated with every change you make
2. RT Overview
RT two ways:
- Used as IPR rendering in Maya (left Image) where it shows in the VFB
- RT can also be used in a Maya Viewport (right image)
- In the viewport, select Vray RT as the panel’s Renderer
- RT can run on CPU or on graphic card’s GPU
- Nvidia cards support CUDA
- Other graphics cards support OpenCL
- Rendering on GPU offloads the processing and can be faster than the CPU depending on the graphics card
3. RT Settings
a) Shading Attributes
- Trace Depth – maximum number of reflection and refraction bounces. If any individual materials have a higher Trace Depth specified, V-Ray will cap them at this global value.
- GI depth – Number of bounces for GI rays. Lower values decrease render times, but at a loss of accuracy.
b) Rendering Values
- Max render time (min) – sets a maximum time limit for progressive renders. When this limit is reached, V-Ray will stop the render and output the frame.
- When rendering animations, you should set this value to allow V-Ray to finish one frame and move to the next once the time limit is reached. Without a value set, V-Ray will continue to refine the single frame until it is manually stopped.
- Max paths per pixel – This limits the maximum quality of the RT render before stopping and/or moving on to the next image in an animation.
4. Animation with RT
- Rendering Animation
- First, turn on Animation in the Render Settings’ Output tab and set your frame range
- Next, set a value for either Max render time (min) or Max paths per pixel
- Then select Render > Render Animation with V-Ray RT
- RT Rendering is done through IPR window or through a Viewport
- RT rendering is Progressive and gives you a quicker view of the entire image
- Gives a good ability to preview rendered results as you change your scene
- Great for changing shaders and or lighting
- RT results are identical to production rendering with Progressive sampling mode in Maya Batch
Time to see it work!
Time to do it yourself!
Dialing in the right values
- Start an RT render with IPR
- Graph the network for the Car_Blend material
- Adjust the Diffuse Color of the Car_Coat material
- RT will update as you change the colors
Find more training resources listed below: