# Identify where the Noise is coming from  ![](https://www.sidefx.com/docs/houdini/icons/MISC/karma.svg) **AOVs for Analyzing Noise** | | | | | -------------------------- | ----- | --------------------------------------------------------------------------------------------------------------- | | `C` | rgba | Beauty image. Identify aliased outlines, which would call for more pixel samples. | | `cputime` | float | Identify slow-rendering objects, which might need object-specific properties, or other optimizations. | | `indirectraycount` | int | Can be used to determine if Max Secondary Ray samples is being reached or not. | | `primarysamples` | int | How the Pixel Oracle is affecting the primary/path traced samples. | | `directdiffuse` | rgba | Direct diffuse samples. | | `directemission` | rgba | Direct emissive samples. | | `directglossyreflection` | rgba | Direct reflection samples. | | `directvolume` | rgba | Direct volume samples. | | `glossytransmission` | rgba | Refractive surfaces. | | `indirectdiffuse` | rgba | Indirect diffuse samples. Emissive geometry set to _Treat As Light Source_ will be included here. | | `indirectemission` | rgba | Indirect emissive samples. These rays come from emissive materials (as long as _Treat As Light Source_ is off). | | `indirectglossyreflection` | rgba | Indirect reflection samples. | | `indirectvolume` | rgba | Indirect volume samples. Requires **Volume Limit** of 1 or higher. | | `sss` | rgba | Materials with sub-surface scattering. | # Other ## Denoise An effective strategy when denoising is to render and denoise at 2× resolution. Because this _quadruples_ the total number of pixels, you should also _reduce_ the pixel samples by 25%. See [Rebelway’s excellent overview](https://www.youtube.com/watch?v=dgK5i0cex1Q&t=2820s) for more details on this technique. ## Crop mask - https://noahhaehnel.gumroad.com/l/Calculate-Datawindow - When you have render layer, you have a lot of empty spaces around the object, it is wasted time in render. ## .RAT files conversion - https://www.sidefx.com/docs/houdini/ref/utils/iconvert.html - https://youtu.be/L51DUKjrkIo?t=658 ## MIP MAP [[KARMA MIPMAP]]