Cubemap Assembler

Every game artist has been there: you've rendered out six nice cubemap faces, and now you have to hand them to a tool that wants one .dds file with a specific face order, and the moment you get the order wrong the sky looks like a funhouse mirror. Cubemap Assembler does that packing step inside ComfyUI - it takes six images and writes a proper DDS cubemap with compression and mipmaps, no external texture utility required.

It's the natural endpoint of this pack's DDS pipeline: generate or load six faces (the sibling Equirectangular to Cubemap node produces them from a panorama), then feed them straight in here and get a cubemap.dds out.

How it works

Under the hood it uses the bundled DirectXTex tooling (texassemble/texconv) that the pack ships in its bin/ folder. The face inputs follow the DirectX convention, which is the order every game engine and most texture tools expect:

• pos_x (+X, Right), neg_x (−X, Left)
• pos_y (+Y, Top/Up), neg_y (−Y, Bottom/Down)
• pos_z (+Z, Front), neg_z (−Z, Back)

Get this order wrong and the node still produces a valid file - it'll just be wrong when your engine loads it. That's the single most common mistake, so label your faces as you go.

Inputs that matter

• The six faces - pos_x/neg_x/pos_y/neg_y/pos_z/neg_z, all IMAGE. They don't have to be the same size; the node normalizes them.
• format (default BC6H_UF16) - BC6H is the right call for HDR environment cubemaps; BC1_UNORM for diffuse/skybox color; BC7_UNORM for highest quality at bigger files.
• output_color_space (default Linear) - environment maps are almost always Linear. Only flip to sRGB if you're baking a color cubemap for a tool that expects it.
• filename_prefix (default cubemap) - output is named <prefix>.dds.
• output_path (optional) - absolute path; empty means ComfyUI's output folder.
• mipmap_levels and mipmap_filter - Full Chain with the default Box filter is fine for 99% of cases.

It's an output node: no outputs, it just writes the file.

Install

Same pack as the rest of Leputen-Utils:

cd ComfyUI/custom_nodes
git clone https://github.com/lilquail/ComfyUI-Leputen-Utils

Restart ComfyUI, find it under Leputen-Utils → DDS. The texconv/texassemble binaries come bundled in bin/ - on Windows they just work.

Troubleshooting

• "texconv not found" - on Windows the DLL ships in bin/, but if you moved things around, check it's there. On macOS/Linux you need to drop the right libtexconv.dylib/libtexconv.so from the Texconv-Custom-DLL releases into bin/.
• Sky looks mirrored/wrong after load - face order. Recheck +Y (top) vs −Y (bottom) and +Z (front) vs −Z (back) first, before suspecting the compression.
• E_NOINTERFACE / RPC_E_CHANGED_MODE warnings in the console - the pack's docs say ignore these; the node falls back to the texconv.exe subprocess and continues.
• HDR env maps look washed out - you probably picked sRGB. BC6H + Linear is the pairing for HDR.

One tip: keep filename_prefix descriptive (env_street_day not cubemap) because every subsequent save in this pack is also called prefix_00001 by default. You'll thank yourself later.