Corona Bitmap Shader - C4D
In addition to the below content, see also: Corona Bitmap Shader at Chaos Docs
When using Corona Renderer, bitmaps can be loaded using two supported shaders:
- Corona Bitmap Shader
- Cinema 4D native Bitmap shader
Both shaders will produce almost identical results; however, using the Corona Bitmap over the Cinema 4D Bitmap shader has some advantages.
Note: Currently, the V-Ray HDRI loader should not be used with Corona Renderer, as it may produce incorrect results and cause additional issues, for example, when using distributed rendering!
1. Corona Bitmap Features
1.1. Rendering speed
In most cases, using the Corona Bitmap node will result in faster rendering:
Sample scene using textures loaded with Corona Bitmap only. Render time - 1:56 (mm:ss).
The same scene is rendered with all textures converted from Corona Bitmap to native Cinema 4D Bitmap.
Rendering time - 2:29 (mm:ss).
The difference may not seem big in such quick rendering, but it will be definitely noticeable in the long run.
1.2. Various filtering modes and blurring
The Corona Bitmap node offers various filtering methods, which affect the appearance of the texture, and can also be used to further decrease render times:
Example 1 - Low-resolution bitmap used as a bump map:
This is the default method, which balances rendering speed and quality. If the texture is in low resolution, pixelated edges may be visible on closeups.
This filtering method is slightly slower; however, it provides better quality in the case of low-resolution textures. The edges are much more smooth than with bilinear filtering selected.
Example 2 - HDRI environment:
Nearest filtering. Render time - 01:28 (mm:ss).
Bilinear filtering. Render time - 01:40 (mm:ss).
Example 3 - Blurring:
Regardless of the filtering type selected, blurring can also be adjusted by modifying the Blur offset value:
Bilinear filtering. Blur offset = 0%.
Bilinear filtering. Blur offset = 25%.
Bilinear filtering. Blur offset = 50%.