Texel Density in Blender: consistent texture detail
To keep neighboring Blender objects consistently detailed, compare their Texel Density: the number of texture pixels per unit of surface length. Then adjust image resolution or UV scale. Giving every material a 4K map does not produce equal density: those pixels cover a large panel and a small prop very differently.
What Texel Density measures
Density is conveniently expressed in px/cm or px/m. More pixels covering the same surface length allow an image to represent more detail. Keep the measurement units consistent when comparing assets.
For a square plane occupying the entire square texture, the calculation is simple: divide the image width by the model width. A 4096 × 4096 map on a plane 200 cm wide gives 20.48 px/cm. A 2048 × 2048 map on a plane 100 cm wide gives the same 20.48 px/cm.
On a complex model, other faces and empty gaps take up part of the image. Object dimensions alone are therefore insufficient: the UV layout matters too. Enlarging a UV island allocates more pixels to it at the same image resolution.
Choose detail for the working camera
First establish the viewing distance and how close the camera will get to the objects. A fixed wide shot and a close-up of one prop have different requirements. In an architectural scene, this helps distribute detail between nearby furniture, small accessories and distant surfaces.
Camera distance does not change the model’s calculated px/cm. It changes how visible individual pixels become and how much detail the final image needs. There is no universal value for every interior: choose a reference object that looks good from the required viewpoint, then compare neighboring assets with it.
Check the actual dimensions of imported models before comparing them. A scale error makes density comparisons misleading, even when the material itself looks familiar.
Measure with Texel Density Checker
The Texel Density Checker add-on provides measurements in the UV Editor. Its official documentation covers calculations for an object or selected faces. Check installation and compatibility on the add-on’s official page.
Texture Size specifies the resolution used for the calculation. Changing this field does not replace the texture file in the material. For a meaningful comparison, the value must match the map actually used.
- Open UV Editing and select an object with an existing UV layout.
- Set Units = px/cm in the Texel Density Checker panel.
- Enter the image resolution in Texture Size.
- In Edit Mode, check Selected Faces: enabling it limits the calculation to the selected faces.
- Click Calculate TD and record Density. Repeat for the neighboring object using the same units.
Choose resolution for each object
A perforated panel and a hammer show why identical maps can be excessive for small props. The panel’s 4K map gives approximately 26.5 px/cm. The hammer’s 1K map gives approximately 28 px/cm. Their image resolutions differ, but their densities are close.
Reducing the large panel’s map to the hammer’s resolution makes its surface noticeably less detailed. Leaving a large map on the small hammer gives it far more pixels per unit of surface than its neighbor. These teaching values illustrate the principle; they are not standards for every scene.
Change the resolution of the actual maps, verify Texture Size and recalculate Density. Consistency does not require giving every object the largest available file: its dimensions, UV layout and appearance from the working camera matter more.
When to change UV scale
Another way to match density is to change the area an island occupies in the image. At a fixed resolution, enlarging the island increases its density; shrinking it reduces density. This is useful when several props share one texture set.
For numerical matching, the official Texel Density Checker documentation describes Set TD. The panel version shown has a Set TD field and a Set My TD button: enter the target density and apply it to the intended selection. Then run Calculate TD again. This operation is described from the add-on documentation; the main panel-and-hammer example matches detail by choosing image resolutions.
For a repeating texture, UV scale also changes the visible pattern size. After editing, check that bricks, tiles or wood grain retain a suitable physical scale. High density alone does not fix a stretched UV layout.
If maps were uniquely baked for the existing UVs, do not change the islands without planning a texture transfer or rebake: the image is tied to the old coordinates. For such a finished asset, first consider changing map resolution while preserving its UVs.
Recheck density after building an atlas
Small props can share a texture atlas. Each then receives part of a shared image rather than the entire file. Use the atlas dimensions for the calculation and check each object’s UVs within it.
Recalculate density after packing the islands: if their scale changed, the previous readings no longer describe the result. Tight packing helps use empty space, but does not guarantee enough detail on every surface. If the required islands do not fit at the chosen density, reconsider image size, atlas contents or the requirements for less visible parts.
Check the result in the scene
Compare neighboring objects from the working camera and the closest planned viewpoint. First assess whether their detail is consistent, then whether it is sufficient for the task. A close-up may need a separate solution even when average Density readings look tidy.
Before the final render, verify model dimensions, use the actual map resolutions in the calculation and measure density again after UV or atlas changes. Save the chosen reference with the scene settings so you can bring the next assets into line with it.
Technical documentation: Texel Density Checker — official project · Calculate TD · Set TD · Blender: baking and UVs
Related tutorials
Source of the article and frames: On Mars 3D — Texel Density Made Simple (Game Art Workflow)