Blender UV unwrap: how to unwrap a model, check stretching and paint a texture

A UV map tells Blender which part of a flat image lands on each face of a 3D model. This guide covers seams, the unwrap methods, the UV Editor, stretch checks and island packing, then painting a texture in Texture Paint mode, with the menu names of Blender 5.2.

What UVs are and why you unwrap a model

U and V are the two axes of the flat texture space, named so they are not confused with X, Y and Z. Each vertex of the mesh gets a point in that space and each face a polygon, and the image covers every face according to where its UVs sit. The manual compares unwrapping to cutting a cardboard box along some edges and laying it flat. Each flat piece is a UV island.

Image textures, texture painting and baking all need UVs. Procedural textures such as Noise use Generated coordinates by default, so they work without them; the guide to textures in Blender covers both kinds. Mesh primitives get a default UV map (their Generate UVs option is on by default), but it stops fitting once you model, so unwrap when the geometry is close to final.

How to UV unwrap in Blender, step by step

1. Click the UV Editing workspace tab at the top of the window. It shows a UV Editor next to a 3D Viewport.
2. Select the object and enter Edit Mode (Tab): all unwrapping happens there.
3. Mark seams where the surface should be cut.
4. Press A to select everything, then U and choose Unwrap Angle Based. The same commands sit in the UV menu of the 3D Viewport header.
5. Fine-tune the result in the Adjust Last Operation panel, bottom left, without starting over.

Mark seams

A seam is a cut line where the UV map is allowed to split. Switch to Edge Select mode (2), select the edges, then choose Edge > Mark Seam (Ctrl+E opens the same menu). Clear Seam removes one.

Hide seams where nobody looks, such as the back of a cylinder or the outer edge of an ear. The manual's rule is as few seams as possible with as little stretching as possible. To check that a seam loop is closed, switch to Face Select mode and press L over a face: Select Linked stops at seams, so if the selection spills over, the loop has a gap.

Unwrap and its three methods

Unwrap cuts the selected faces along their seams, flattens them and lays them out, overwriting existing UVs. The U menu offers three methods:

• Unwrap Angle Based: Angle Based Flattening (ABF), the default.
• Unwrap Conformal: Least Squares Conformal Mapping (LSCM), usually less accurate, but it can do better on simple objects.
• Unwrap Minimum Stretch: added in Blender 4.3, it runs the SLIM algorithm over several iterations to reduce both area and angle distortion.

In Adjust Last Operation, Margin sets the space between islands, and Blender 5.2 adds Original Bounds, which keeps islands in their previous area instead of re-packing them.

The other unwrap methods

• Smart UV Project needs no seams: it splits the mesh wherever the angle between faces exceeds the Angle Limit (66 degrees by default) and projects each group flat. The manual suggests it for mechanical objects and architecture.
• Cube Projection projects each face onto the most suitable side of a virtual cube. The islands overlap, so run Pack Islands afterwards.
• Cylinder Projection and Sphere Projection wrap faces around a virtual cylinder or sphere; the sphere is flattened like a world map, for eyes or planets.
• Project from View uses the faces as seen in the 3D Viewport, handy for a photo of the real object. Surfaces that recede from the view get stretched.
• Follow Active Quads extends the UV shape of the active quad to the connected selected quads. Give that face a clean shape first, or its distortion spreads.
• Lightmap Pack places each face separately to fill the texture. It suits lighting baked for real-time rendering, not hand painting.

The UV Editor and the UV Editing workspace

The UV Editor shows the UV map over an image. Transforms work as in the 3D Viewport: G moves, R rotates, S scales, and X or Y locks an axis.

Since Blender 5.0, Sync Selection is on by default: the UV Editor shows the UVs of every face and shares its selection with the 3D Viewport. Turned off, it only shows the UVs of the faces selected in the 3D Viewport. Press 4 to toggle UV Island Selection, or hover over a UV and press L, to grab a whole island.

Check stretching with the overlay and a test grid

Distortion means squares of the same size in the image come out at different sizes on the model. In the UV Editor, in Edit Mode, open the Overlays drop-down and tick the box in the UV Stretch section (Display Stretch). Blue means little distortion, red a lot. The Angle type compares angles between mesh and UV faces; Area compares their sizes.

For a visual check on the model itself:

1. In the UV Editor, choose Image > New (Alt+N) and set Generated Type to UV Grid or Color Grid, which labels each square with letters and numbers.
2. In the Shader Editor, load it in an Image Texture node connected to the Base Color of the Principled BSDF.
3. In Material Preview shading, the squares should stay square and the same size everywhere.

Where the grid stretches, add a seam and unwrap again, or try UV > Minimize Stretch.

Pack Islands and set the margin

Run UV > Average Islands Scale first, so all islands get approximately the same scale and no part of the model ends up with fewer pixels. The guide to texel density in Blender goes further. Then select all UVs and choose UV > Pack Islands: Blender scales, moves and rotates the islands to fill the UV square with a margin between them.

With Margin Method set to Fraction, Margin is a fraction of the UV square: on a 1024 × 1024 texture, 1/1024 (about 0.001) leaves 1 pixel around each island. For n pixels, enter n divided by the texture width. Pack To places the islands in the closest UDIM tile by default; the guide to UDIMs in Blender covers layouts spread over several tiles.

What a good UV unwrap looks like (example)

You can judge a UV unwrap with five checks, each one tied to a tool that ships with Blender. A tidy-looking layout in the UV Editor proves little on its own; the checks below do. A worked example on a cylinder and a cube follows.

Five checks for a clean UV map

1. Little stretching. With Display Stretch on, the islands stay mostly blue. With a UV Grid or Color Grid image on the model, the squares stay square and the same size. Color Grid labels its squares with letters and numbers, so an island that is flipped or turned on its side shows up as mirrored or sideways labels.
2. Hidden seams. Seams sit where the camera rarely looks or where the model already has a break: the back of a cylinder, under the chin, along a hairline. The manual's rule still applies: as few seams as possible, with as little stretching as possible.
3. Islands in proportion and oriented. All the islands of a model should share one texel density, so the texture covers every part at the same resolution. UV > Average Islands Scale gets them close, and the Area type of Display Stretch highlights differences in scale between mesh and UVs; the texel density guide shows how to measure it. Straight parts such as the side of a cylinder or a plank read best when they line up with an axis: UV > Align Rotation turns whole islands to the U or V axis, and UV > Align (Shift+W) > Straighten lines up a row of UVs between its endpoints.
4. A margin between islands. Pack Islands leaves the Margin you set around every island. The section above shows how to turn it into pixels for your texture size.
5. No overlap, unless you mean it. Overlapping faces share pixels, as the common mistakes below explain. The deliberate exception is symmetry: the manual suggests seaming a head or a body along its mirror axis so both halves can sit on the same texture space and share pixels. If you stack halves that way, tick Merge Overlapping in Pack Islands (it is off by default) so the stacked islands are packed together and keep their relative position. Select > Select All by Trait > Overlap finds the overlaps you did not plan.

Example: unwrapping a cylinder step by step

1. Add a cylinder with Add > Mesh > Cylinder, enter Edit Mode and switch to Face Select mode (3).
2. Click the top cap, Shift-click the bottom cap, then choose Select > Select Loops > Boundary of Selection. Blender switches to edges and selects the rim of each cap. Mark them with Edge > Mark Seam: each cap becomes its own island.
3. In Edge Select mode (2), click one vertical edge on the side that faces away from the camera and mark it as a seam too. That is the manual's own example: the back-most edge of the cylinder, so the seam stays out of sight.
4. Press A, then U > Unwrap Angle Based. You get three islands: a strip for the side and a disc for each cap.
5. Run the five checks: Display Stretch and a Color Grid for stretching, Align Rotation so the strip lies straight, Average Islands Scale, then Pack Islands with a margin.

A cube follows the same logic. It has 12 edges; mark 7 of them as seams. Take one vertical edge at the back, then three of the four edges around the top face and three around the bottom face, leaving uncut the edge each of those faces shares with the front. Unwrap then lays the cube out as a cross, like the flattened cardboard box the manual uses to explain unwrapping.

How to use UV editing in Texture Paint

Texture Paint mode paints into an image through the UV map: a stroke on the model is projected onto the UVs and written into the pixels they cover. If the mesh has no UV map, Blender shows a warning and offers Add Simple UVs, a cube unwrap followed by a pack, which the manual still advises replacing with a proper unwrap.

1. Open the Texture Paint workspace

It puts the 3D Viewport in Texture Paint mode next to an Image Editor already in Paint mode. You can paint in either, and each stroke shows up in the other at once.

2. Create the image to paint on

1. In the 3D Viewport header, open the Texture Slots popover and leave Mode on Material.
2. Click + and choose Base Color (Roughness, Metallic, Normal and Bump are among the other choices).
3. In the Add Paint Slot dialog, set the name and size, 1024 × 1024 by default, then click Add. The fill color starts from the material's current Base Color.

Blender adds an Image Texture node with the new image and connects it to the Principled BSDF, creating a material if there is none. The manual notes that painting stays responsive with square images whose sides are a power of two.

3. Paint while watching the UVs

Brushes have been assets since Blender 4.3: pick Paint Hard or Paint Soft from the asset shelf at the bottom of the 3D Viewport, set Color, Size and Strength in the tool settings, and paint.

The Image Editor draws the UV layout over the image, so you see which island each stroke lands on. If the lines are missing, open its Overlays and enable Display UVs in the Geometry section.

To move UVs, the manual sends you back to the UV Editor, in Edit Mode. Moving UVs after painting makes faces pick up different pixels, so finish the layout first. If a face partly behind the view refuses paint in perspective, zoom out or switch to an orthographic view.

4. Save the image

Painting changes the image in memory only, and Blender does not save it automatically. An asterisk next to the Image menu of the Image Editor flags unsaved changes. Use Image > Save (Alt+S), Save As for a new file, or Image > Pack to store it inside the .blend file. Since Blender 5.2, saving the .blend file with modified images opens a dialog that offers to save them too.

Common mistakes

• Overlapping UVs. Faces on the same part of the UV map share pixels: paint one and the other changes, and bakes come out wrong. In the UV Editor, Select > Select All by Trait > Overlap finds them and Pack Islands separates them.
• Scale not applied. Unwrap ignores the object's scale. With a non-uniform scale, Blender reports "Object has non-uniform scale, unwrap will operate on a non-scaled version of the mesh" and the texture stretches. In Object Mode, press Ctrl+A > Scale, then unwrap again.
• Image not saved. The paint is gone after reopening the file because the image was never saved or packed. See step 4.

What next

With clean UVs, you can bake detail and lighting into images, as the guide to texture baking in Blender explains, and the guide to normal maps in Blender covers the maps you bake from a high-poly model.