UV Laboratory: From Blender to a Finished UV Layout

STEP 01

Send Your Model from Blender

Follow a complete UV workflow: send a model from Blender, mark seams, shape islands, control texture density, pack and send the finished UVs back.

In Blender:

1. Switch to Object Mode.
2. Select the mesh objects you want to unwrap.
3. Open the Alpaca panel in the 3D Viewport sidebar.
4. Under UV Operations, click Send.

Your model opens in Alpaca3D’s UV Lab. The UV layout and 3D viewport share the same selection, so you can work in either view.

STEP 02

Navigate the Viewports

Use these controls in the 3D viewport:

Use pan and zoom to navigate the UV view.

The viewport display controls let you inspect the checker pattern, distortion, constraints, and wireframe. Switch between these views as you work to evaluate the layout on both the UV islands and the model.

STEP 03

Select Geometry

Use the number keys to switch selection modes:

Hold Shift to add to your selection. In edge mode, use Ctrl to select an edge path.

Press A to select all, or double-tap A to deselect.

These are the default shortcuts. Command shortcuts are displayed beside their buttons; configurable bindings can be changed in Hotkeys.

STEP 04

Clear Existing Seams and Isolate a Part

If you want to start the unwrap from scratch:

1. Select the whole model.
2. Click Clean in the UV section, or press X, to remove existing seams.

To work on one part without the rest of the model getting in the way:

1. Clear your selection.
2. Hover over the part.
3. Press Alt + H to isolate it.

Press Ctrl + H to show everything again.

If geometry is already selected, isolation acts on that selection. Clearing it first makes the hovered part the target.

STEP 05

Mark Seams with Real-Time Unwrapping

Switch to edge mode with 2, then select the edges you want to turn into seams. Use Ctrl to build a path along the surface.

Click Mark, or press C, to mark the selected edges.

With automatic seam unwrapping enabled, the UV layout updates immediately. Watch the distortion display as you add cuts, and check whether the resulting islands are becoming easier to flatten.

You can select and mark edges in either the 3D viewport or the UV view.

For faster seam placement, use the Cut tool to mark seams directly on the model. Apply the same approach to the remaining parts, isolating sections when needed.

STEP 06

Arrange Your UV Islands

Use these shortcuts to transform your selection:

You can also hold Space and drag:

• Left mouse button: scale.
• Right mouse button: rotate.
• Middle mouse button: move.

After marking the seams, select all and press U to unwrap. Press P to create an initial packed layout.

This first packing pass helps organise the islands before further refinement.

STEP 07

Shape Islands with Constraints

Open Advanced Settings in the UV section to access the constraint tools.

Constraints control how selected parts of an island are shaped during unwrapping and alignment.

Horizontal and Vertical Constraints

Select an edge chain and apply a horizontal or vertical constraint to straighten that side of the island.

These are useful for aligning boundaries that should follow a clear horizontal or vertical direction.

Straight-Line Constraints

Use a straight-line constraint for an angled section that should remain straight.

You can place multiple straight constraints one after another around an island, allowing different sections of the boundary to follow different directions.

To remove selected constraints, press Alt + D.

Shape Constraints

Circle, square, and triangle constraints provide a quick way to give suitable islands a regular boundary.

Choose a shape that fits the geometry, then inspect the result in both viewports. A regular outline is useful only when it also produces an acceptable distribution of distortion.

Automatic Constraints and Auto Grid

Automatic constraints can reduce manual setup by identifying suitable directions on an island.

Auto Grid is useful for compatible grid-like topology.

Treat automatic results as a starting point: inspect the island and refine the constraints where necessary.

Automatic Unwrapping for Constraints

Keep automatic unwrapping for constraints enabled to see changes as you apply them.

If you prefer to define several constraints before recalculating the layout, disable this option and run Unwrap afterward.

STEP 08

Redistribute Distortion

After shaping an island, run Interior UV Alignment with Y.

This adjusts the UV layout to redistribute distortion while respecting the applicable constraints and locks.

Enable Continuous Relaxation if you want alignment to continue updating as you work. This is useful when refining constraints and watching how the island responds.

Inspect the result after each meaningful change rather than judging the island by its outline alone.

STEP 09

Protect Finished Islands with Lock Shape

Use Island Locks when some parts of the layout should be protected from further changes.

Lock Shape preserves an island’s shape during subsequent adjustments. It still allows movement, rotation, and uniform scaling unless those properties are locked separately.

This is particularly useful for grid-shaped or carefully straightened islands that you want to preserve while refining the rest of the layout.

STEP 10

Control Where Texture Detail Goes

Not every part of a model needs the same amount of texture space.

Vertex Density

Use the Vertex Density brush to give important areas more room in the UV layout.

In the video example, the eye receives extra attention because it is a visually important feature.

Density Fill

Use Density Fill to reduce the texture space allocated to less visible or less important parts.

Balance these adjustments against the needs of your asset. Giving one area more space leaves less available for others.

STEP 11

Pack the UV Layout

Press P to start packing.

In Packing → Advanced Settings, configure the layout for your project:

• Texture aspect ratio.
• Spacing between islands.
• Margin around the texture border.

Let the packer search for a better arrangement and monitor the fill percentage.

Evaluate the result alongside your spacing and density requirements. A higher fill percentage alone does not guarantee that the layout is better suited to your asset.

STEP 12

Refine the Layout with Inflate

For an optional finishing pass, use Contour Deformation, also called Inflate.

This expands island boundaries into available gaps. It can help allocate additional UV space to parts of the model, but it also changes island shapes.

A useful sequence is:

1. Apply Lock Shape to islands whose shapes should be preserved.
2. Press I to run Contour Deformation.
3. Press Y to run Interior UV Alignment.
4. Inspect the updated layout and distortion.

Compare the result before keeping the changes. Use this step where it improves your layout rather than applying it automatically to every asset.

STEP 13

Send the Finished UVs Back to Blender

When you are satisfied with the result, click Send to Blender.

The updated UVs are applied to your model in Blender.

The bridge also preserves constraint information, allowing you to send the model back to Alpaca3D and continue refining the layout without rebuilding those constraints.

STEP 14

Workflow Checklist

1. Send the model from Blender.
2. Clear unwanted seams and isolate the part you want to work on.
3. Mark seams and inspect the real-time unwrap.
4. Shape islands with constraints.
5. Redistribute distortion with Interior UV Alignment.
6. Protect finished shapes with Island Locks.
7. Adjust local density.
8. Pack the layout.
9. Optionally refine with Inflate and alignment.
10. Send the finished UVs back to Blender.

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