Overview
Combines two Surface values into one Surface.
It composites not only the image but also height, normals, emission, roughness, material IDs, and face IDs. Use it to place grime over a floor Surface, metal parts on a wall, or another face part onto part of an isometric face.
Output dimensions always match base. Position overlay with offset_x / offset_y.
Usage tips
- This is the Surface equivalent of image
blend. Composite parts before lighting; combining already-lit images breaks lighting consistency. - Height handling is key. Use
height_modeto choose whether the part sits above the base and determine whether it protrudes or sinks in. - Turn
rebuild_normal_from_heightON after compositing to rebuild normals across the step for more natural lighting. - Inspect the result by switching submap previews such as H for height and N for normals.
Common pitfalls
- The overlay does not rise under lighting: its height was not raised through height_mode/offset, or normals were not rebuilt. It may overlap visually, but lighting reads height and normals.
overlayis clipped: output dimensions always follow base. offset positions the overlay, and overflow is cropped.
Examples
- Use a floor Surface from
Grid Patternasbase, then overlay a grime or puddle Surface. - Place a small metal-part Surface over a wall from
Surface Plane, usingid_policy=OverlayVisibleto include its metal ID. - When attaching a window frame to a wall, use
height_mode=下地より高くする,height_offset=0.05〜0.15, andrebuild_normal_from_height=ON. Strengthen cast shadows inSurface Light Previewto make the frame appear slightly raised. - For a flat sticker-like overlay, use
map_policy=AlbedoOnlyandid_policy=KeepBase. - Turn
wrap_xorwrap_yON to composite across an edge in a tileable asset.
How to check the result
- Create two
Image to Surfacenodes and connect one tobase, the other tooverlay. - Change
offset_x/offset_yand confirm that the overlap position moves. - Switch the
Surfacepreview amongA,H,ID, andF, confirming that maps and IDs overlap in the same place as the visible image. - Set
height_mode=下地より高くするandheight_offset=0.1, then check in theHpreview that only the overlay becomes brighter. - Set
rebuild_normal_from_height=ONand check for color changes at the raised edge in theNpreview. - Connect
Surface Light Previewand confirm that the composite behaves as a Surface containing emission, normals, and face IDs.
Related nodes
blend— composite ordinary images when a Surface is unnecessarysurface_light_preview— light the composite resultsurface_rebuild_normal— rebuild normals as a separate operationsurface_set_map— replace individual submaps