Texturing STL Workflow (Vertex Group + Displace) — Full Detail with Purpose
1. Start a new project

Purpose: Ensure you’re working in a clean Blender environment and your STL is properly oriented for further operations.

Open Blender.

Go to File → New → General.

Import your STL (File → Import → STL).

Make sure the object is selected.

Orient your object correctly (e.g., R -90 Enter), so all further operations match the intended real-world orientation.

2. Prepare the mesh

Purpose: Identify whether the STL has enough geometry to support texture detail. Most STLs are too coarse and need remeshing.

Switch to Edit Mode (Tab).

Switch to Face Selection (3).

Inspect the faces you plan to texture.

Note areas that are too large or flat; these will need remeshing.

3. Remesh for adequate resolution

Purpose: Generate a uniform mesh that can cleanly accept displacement detail.

Switch to Sculpt Mode (Ctrl+Tab → Sculpt Mode).

Open the Remesh menu.

Set Voxel Size (e.g., 0.18). Smaller = finer, larger = faster.

Click Remesh and wait until Blender finishes.

Switch back to Edit Mode (Tab).

4. Create a vertex group

Purpose: Define which parts of the mesh will receive the displacement texture.

Open Object Data Properties (green triangle).

Click + under Vertex Groups.

Name it according to the part you plan to texture (e.g., “Grip_Texture”).

This group will control the displacement effect.

5. Add seams (if needed)

Purpose: Help Blender unwrap UVs properly and minimize texture distortion on wrap-around areas.

Switch to Edge Selection (2).

Identify edges that wrap fully around the model or will cause UV stretching.

Select those edges.

Go to Edge → Mark Seam.

Place seams in inconspicuous locations whenever possible.

6. Select faces for the vertex group

Purpose: Accurately assign which faces will receive the displacement texture.

Switch back to Face Selection.

Select initial face(s).

Use Select → Linked → Linked Flat Faces.

Press Ctrl + repeatedly to extend the selection.

Press Ctrl - the same number of times to refine interior edges.

Manually add any missing faces with Shift + Select.

Assign selection to your vertex group.

Click Select in the vertex group panel to verify coverage.

7. UV unwrap

Purpose: Prepare the faces so textures map correctly during displacement.

With vertex group faces selected, go to UV → Unwrap → Angle-Based.

Ensure all desired faces are included.

8. Add displacement modifier

Purpose: Apply the texture to the mesh using your vertex group and UVs.

Switch to Object Mode (Tab).

Go to Modifiers → Add Modifier → Displace.

Click New next to Texture.

Set Coordinates to UV.

Assign your vertex group in the modifier.

Open the Texture Properties tab (checkerboard icon).

Click Open and select your image (B+W preferred).

Adjust texture mapping as needed: Repeat X/Y, Flip axes, Min/Max X/Y.

Return to Displace Modifier tab.

Adjust Strength and Midlevel until the texture height is correct.

Repeat for multiple vertex groups if needed.

9. Decimate and finalize

Purpose: Reduce mesh density for export while preserving the displacement detail.

Add Decimate Modifier (Add Modifier → Decimate).

Set the ratio (e.g., 0.18).

Inspect the mesh to confirm detail retention.

Export: File → Export → STL.

Save your Blender project for future edits.