Check texture maps before you export them

Texture maps only look right in another program when that program reads them the way they were written. A normal map with the wrong green direction makes bumps look like dents; a packed map read with the wrong channel order turns roughness into metal. Texture Lab's Export compatibility report lists these facts in one place, and the same report travels inside the material ZIP.

Open the report

Choose Texture Lab in the Renderloom header. On a first visit the original sample Weathered stone opens; otherwise pick it under Original sample textures. Below the map cards, open Export compatibility report. For the sample it reads:

• Every exported map is 128 × 128 pixels. All maps share the source size, so they line up exactly in any material.
• The normal map uses +Y (OpenGL-style) tangent space. This is what glTF, Blender and most OpenGL-based tools expect.
• The source image has no transparent pixels.
• Custom packed map channels: the source chosen for red, green, blue and alpha under Custom channel packing.
• ORM map channels: red = cavity approximation, green = roughness, blue = uniform metallic.

The notes underneath explain how to treat the files. The base color is display sRGB; every other map is a data texture, so import it without a color profile. Height, normal, roughness and cavity are estimates derived from brightness, not measured properties.

Watch it follow your settings

The report is recalculated on every edit. Tick Flip normal green (−Y) and the second line changes to The normal map uses −Y (green flipped, DirectX-style) tangent space. Use that setting for programs that expect DirectX-style normals, and leave it off for glTF.

Import an image with transparent areas through Import texture image: the report counts the transparent source pixels, for example "2560 source pixels are transparent." Transparent colors are blended over white in the exported base color, so check edges where the image fades out. Alpha stays available as a height source under Height source channel.

Change a channel under Custom channel packing, for example green to Smoothness (inverted roughness), and the packed-channel line updates with the same names you picked.

What the material ZIP contains

Download material ZIP saves eleven files:

• baseColor.png, height.png, normal.png, roughness.png, ao.png, metallic.png, orm.png and packed.png, all at the size in the report;
• material.renderloom-material.json, the editable recipe including the source image, which you can reopen with Open material project;
• export-report.json, the same facts as the on-screen report in a machine-readable form (dimensions, normal direction, transparent pixel count, ORM and packed channel assignments, notes);
• README.txt, a plain-text summary of the same information plus every setting of the recipe.

The status line confirms the download. Keep the README next to the maps when you hand them to someone else: it answers the usual "which way is green?" question without opening Renderloom.

Limits to keep in mind

The ZIP holds PNG maps and a Renderloom recipe. It is not a glTF material or a 3D model, so you assign the maps yourself in the target program. The ORM green and blue channels map directly to glTF roughness and metallic. ORM red needs its own occlusion texture slot. The light preview in Texture Lab is illustrative and does not prove how the material will render elsewhere.