Heightmaps
Format: We recommend EXR for highest quality.
File Size: The maximum allowed file size for heightmaps is 15MB per file. This limitation is due to automatic compression isn't available at the moment. This limitation will increase in the future.
Texture Size: Maximum size of 4K (4096x4096).
note
Similar to other texture files, we recommend adhering to the power of two rule when creating heightmaps. You can learn more here