How to UV Unwrap in Blender for Game Assets: Fix Stretched Textures and Seam Problems

You made a model in Blender. You applied a texture in Unity. It looks like someone stretched a photograph over a crumpled piece of foil. The wood grain on your crate runs in three different directions on three different faces. The brick pattern on your wall tiles correctly on one side and is completely wrong on the adjacent face.

This is a UV problem. Specifically it is what happens when there is no UV map, or a bad one.

UV unwrapping is one of those topics that gets skipped in beginner tutorials because it is not glamorous and it is genuinely confusing the first time you encounter it. I avoided it for about two months by only texturing things in Unity using tiling materials that did not need a proper UV map. That worked until I tried to put a logo on a crate lid, bake a normal map for a rock, or give a character any clothing detail at all. Then I had to learn it properly.

This guide covers what UV coordinates actually are, how to mark seams and unwrap correctly for game assets, where seams should and should not go, how to check for distortion, and how to get clean UVs into Unity.

What UV Coordinates Actually Are

Every point on a 3D mesh has a position in 3D space — X, Y, and Z. UV coordinates are a second set of positions for the same points, but in 2D space — U and V instead of X and Y. They map each point on the 3D surface to a specific location on a flat 2D image.

Think of it like peeling an orange. The orange is your 3D model. The flat peel is your UV map. Unwrapping is the process of cutting the peel in specific places (seams) so it can lie flat without too much stretching. Where you put those cuts determines how the flat image wraps back onto the 3D surface when you apply a texture.

When there is no UV map, or a broken one, Unity and Blender have to guess how to map the texture — and the guess is almost always wrong for anything other than a perfect cube with tiling materials. When the UV map is correct, a texture maps exactly where you placed it, at the size and orientation you intended.

The Two Workspaces You Need

UV unwrapping in Blender happens across two panels that need to be visible simultaneously.

The 3D Viewport is where you mark seams on the actual mesh.

The UV Editor is where you see and adjust the resulting flat UV map.

The fastest way to set this up: go to the UV Editing workspace tab at the top of the Blender window. This opens a pre-configured split view with the UV Editor on the left and the 3D Viewport on the right. It is exactly the layout you need and it is already there — you do not need to build it manually.

Part 1: Marking Seams

Seams are the cuts you make in the mesh that allow it to unfold flat. They are invisible in the final rendered model — they only exist in the UV data. Getting seam placement right is most of the work in UV unwrapping.

The Golden Rule of Seam Placement

Put seams where they will be least visible on the final model. The inside of a jacket sleeve. The underside of a belt. The back of a character's head where hair covers it. The bottom of a crate that sits on the floor. Seams are cuts in the UV islands, and at the boundary of those cuts textures occasionally show a slight misalignment — hiding that in a place the player never looks costs nothing.

How to Mark Seams

1. In the 3D Viewport, press Tab to enter Edit Mode.
2. Press 2 to switch to Edge Select mode.
3. Select the edges where you want to place seams. You can click individual edges, or hold Shift and click to select multiple. For a loop of edges, Alt+Click selects the entire edge loop at once.
4. With edges selected, go to Edge menu > Mark Seam (or right-click and find Mark Seam in the context menu).
5. Marked seams appear as red edges on the mesh.

For a basic crate: mark seams along four vertical edges (the corners) and along the bottom face edges. This lets the crate unfold into a cross shape — five faces of the box laid out flat, with the bottom face separate. Every face gets its own UV island with minimal distortion.

Part 2: Unwrapping

Once seams are marked, unwrapping is one shortcut:

1. In Edit Mode, press A to select all geometry.
2. Press U to open the UV menu.
3. Choose Unwrap.

Look at the UV Editor on the left. Your mesh should now appear as a flat layout of UV islands within the UV square (the 0 to 1 UV space). Each disconnected region separated by your seams is a UV island.

If the result looks like a chaotic mess of overlapping shapes, either your seams are wrong, you did not select all geometry before unwrapping, or the mesh has some geometry issue like disconnected faces. Undo, check your seam placement, and try again.

Smart UV Project: The Shortcut That Is Not Always a Shortcut

The UV menu also has Smart UV Project, which automatically generates seams and unwraps without you doing any seam placement manually. It works well for simple objects like rocks and terrain chunks where you just need a usable UV map quickly and you will be using a tiling texture rather than a custom-painted one.

For anything with a custom texture, a character, or an object where texture direction matters, Smart UV Project produces UV islands at random angles that make applying directional textures (wood grain, fabric weave, brick courses) very difficult. It is a fast option, not always the right one.

Part 3: Checking for Distortion

Marking seams and pressing Unwrap is easy. Knowing whether the result is good requires checking for distortion — areas where the UV islands are stretched or compressed compared to the actual surface area of the 3D faces.

The Checker Texture Method

This is the fastest way to see distortion visually:

1. In the 3D Viewport, go to the Material Properties panel (the sphere icon in the right sidebar).
2. Add a new material and set its Base Color to an Image Texture.
3. Click New in the image texture node to create a blank image, then in the dropdown next to the filename, choose Generated > UV Grid.
4. Switch the 3D Viewport to Material Preview mode (the sphere icon in the viewport header, or press Z and choose Material Preview).

Your model should now display a black and white checkerboard. Look at the squares: if they are all roughly the same size and shape across the entire model, your UV map is good. If some squares are stretched into rectangles, squashed, or skewed, those UV islands have distortion that will show up on your final texture.

Fixing distortion usually means either adjusting seam placement and re-unwrapping, or manually moving UV vertices in the UV Editor to even out the island shapes. For most game assets, some minor distortion is acceptable as long as it is not in a prominent visible area.

Part 4: UV Islands and Texture Space

Once the basic unwrap looks clean, there are three things to do before exporting.

Pack Islands

In the UV Editor, select all UV islands with A, then go to UV > Pack Islands. This automatically repositions and scales all islands to fit efficiently within the 0-to-1 UV square without overlapping. Blender's packing is decent but not perfect — for complex models, dedicated UV packing tools do a better job, but Pack Islands is fine for most game assets.

Scale Islands by Surface Area

Islands that represent a large area of the 3D mesh should take up more UV space than small detail areas. A character's torso needs more texture resolution than the inside of their collar. In the UV Editor, you can manually scale individual islands (select the island, S to scale) to give more texture space to prominent areas and less to hidden ones.

This is called texel density — keeping the number of texture pixels per 3D surface unit consistent across a model. Perfect texel density means every part of the model has the same texture resolution. You rarely achieve perfect texel density but you want to avoid obvious mismatches like a character face being blurry while their belt buckle is sharp.

Avoid Overlapping Islands (Usually)

Overlapping UV islands mean two different parts of the 3D mesh are mapped to the same area of the texture. This is intentional in some workflows — mirrored characters often have the left and right sides share UV space to double the effective texture resolution on each side. For a beginner, avoid overlapping until you understand why you are doing it, because overlapping UVs cause baking errors and visual artifacts in most standard workflows.

Part 5: Exporting to Unity With Clean UVs

The UV map exports automatically with the FBX file using the same export settings from the Blender Basics guide. No extra steps are needed — the UVs travel with the mesh geometry in the FBX format.

What does require attention:

Multiple UV channels. Blender supports multiple UV maps per mesh. Unity uses UV channel 0 (the first UV map, called UVMap in Blender by default) for the main texture, and UV channel 1 for lightmapping. If you have more than one UV map in Blender, check which one is active (the camera icon in the UV Maps list in the Object Data Properties panel) — the active UV map exports as channel 0.

Flipped V coordinate. Blender and Unity use opposite vertical conventions for UV space — Blender's UV origin (0,0) is the bottom-left; Unity's is the top-left. In practice this means textures appear vertically flipped in Unity compared to Blender. The fix is to check Flip V in Unity's Import Settings under the Model tab, or to flip the texture vertically in Blender before export by selecting all UVs in the UV Editor and scaling them -1 on the Y axis (S, Y, -1, Enter).

Real Example: UV Unwrapping the Blender Basics Crate

If you followed the previous guide and built the crate, here is the UV unwrap process applied to it specifically.

1. Enter Edit Mode on the crate. Press Alt+A to deselect everything.
2. Switch to Edge Select mode (press 2).
3. Alt+Click each of the four vertical corner edges to select those edge loops. Shift+Alt+Click to add to the selection.
4. Also select the bottom face edges.
5. Right-click and choose Mark Seam. The selected edges turn red.
6. Press A to select all geometry, then U and choose Unwrap.
7. In the UV Editor, you should see a cross-like layout of six UV islands — four side faces, the top, and the bottom.
8. Apply a UV Grid checker texture and check the viewport. The squares should be roughly even across all faces.
9. Select all in the UV Editor, go to UV > Pack Islands.
10. Export as FBX using the settings from the Blender Basics guide.

In Unity, assign a material with a wood plank texture to the imported model. The planks should run consistently across the faces without the stretching or rotation errors you would get from a model with no UV map.

Where Beginners Go Wrong

• Not marking any seams and expecting Unwrap to work anyway. Without seams, Blender cannot figure out where to cut the mesh to lay it flat. The result is a jumbled mess in the UV Editor. You must mark seams first.
• Putting seams in visible, prominent areas. The seam itself is invisible, but texture misalignment at seam boundaries is not. Always put seams on edges that will be hidden, in shadow, or at natural material boundaries like where a sleeve meets a cuff.
• Not checking with a checker texture before exporting. Distortion that is obvious with a checker pattern is almost impossible to see by just looking at the mesh without a texture. Apply the UV Grid and check every face before you spend time painting a texture onto a broken UV layout.
• Overlapping UV islands by accident. Pack Islands usually prevents this, but manually moving islands in the UV Editor without checking for overlaps can create problems. The UV Editor has a Highlight Overlapping Islands overlay that turns overlapping areas red — enable it to check.
• Forgetting to apply transforms before UV unwrapping. Unapplied scale on the mesh causes UV islands to come out at wrong proportions. Apply All Transforms (Ctrl+A in Object Mode) before entering Edit Mode and unwrapping, same as the export step in the Blender Basics guide.
• Using Smart UV Project on organic shapes and wondering why the texture looks bad. Smart UV Project creates UV islands at whatever angle Blender decides. For organic geometry this usually means every island is at a different rotation, making directional textures (hair, scales, fabric grain) impossible to apply correctly without manual cleanup.

Troubleshooting

My UV map looks fine in Blender but the texture is still stretched in Unity.

Check the V coordinate flip issue described in the Export section. Also confirm you are using UV channel 0 in Unity's material setup — if a second UV channel was accidentally exported as the primary one, Unity reads the wrong coordinates.

Some faces do not appear in the UV Editor after unwrapping.

Those faces are not connected to any UV map, or they were not selected when you ran Unwrap. Select all (A) in Edit Mode and run Unwrap again. If faces still disappear, check for faces with zero area (completely flat, degenerate faces) that sometimes get dropped from the UV calculation.

My UV islands are all at different scales and some are tiny.

This happens when faces have very different sizes in 3D space — large faces get larger islands, small faces get small ones, and the range can be extreme. In the UV Editor, select all islands and go to UV > Average Island Scale to even them out before packing.

The seams are not visible in Edit Mode even after marking them.

Go to Viewport Overlays (the two overlapping circles icon in the viewport header) and make sure Seams is checked under the Mesh Edit section. Seam display is a viewport overlay that can be toggled off.

My texture has a visible line or gap at the seam boundary in Unity.

This is a texture bleeding issue. In Unity's texture import settings, enable Generate Mip Maps and set the texture's Filter Mode to Bilinear or Trilinear rather than Point. Also make sure there is a small amount of padding between UV islands (Pack Islands has an Margin slider — use a value around 0.02 to 0.05 to add padding between islands).

What to Learn Next in Blender

Once UV unwrapping feels comfortable, two things open up that were not possible before.

Texture baking — rendering lighting, ambient occlusion, and surface detail from a high-poly model into a texture that displays on a low-poly version. This is how game characters get detailed normal maps without needing millions of polygons. It requires a clean UV map on the low-poly model as its starting point.

Texture painting in Blender — painting directly onto the 3D surface using Blender's Texture Paint mode. The paint maps onto the UV layout, so a correct UV map is required before you can paint anything that looks right on the 3D model.

Both of those are deep enough topics for their own guides. The important thing is that neither is achievable without a working UV map — which is why UV unwrapping, despite being unglamorous, is the skill that unlocks most of the interesting things that come after it.

Next Topics To Learn

• Blender Basics for Unity Developers — if you came here before reading the fundamentals guide, start there for modeling, transforms, and the FBX export settings this guide builds on.
• Unity Mobile Optimization Guide — texture size and atlas packing decisions made during UV unwrapping directly affect mobile performance.
• Unity Animator and Animation System Explained — characters with clean UVs and baked textures are the input to the animation workflow covered there.