Packing

Packing#

UV Flow packing can be performed in Edit Mode from the UV menu or from the Cut UV tool settings, in Object Mode from the Object menu or from the Material tab of the Properties Editor, or in either mode by using the hotkey Shift Alt P.

Include#

The Include setting in the UV Flow pack menu determines which faces are packed together.

  • Selected Faces: Packs all selected faces together.

  • Selected Objects: Packs all faces of the selected objects together.

  • Selected Materials: Packs all faces of every object in the scene that shares the same material as the selection (in Edit Mode) or the active material (in Object Mode).

Tip: You can quickly select and pack entire materials in UV Flow by using the buttons underneath the material datablock in the Material tab of the Properties Editor.

Group#

The Group setting specifies which islands are packed into the same UV space.

  • All Together: Packs all islands into a single UV space.

  • By Object: Packs islands based on which object they belong to.

  • By Material: Packs islands based on which material they are assigned to.

The default for Group is By Material, since it is more common to have separeate textures for each material than for each object.

Shape#

The Shape setting controls the accuracy and speed of the packing process.

  • Bounds: The fastest option, which treats each island as a simple rectangle.

  • Convex: Slower than Bounds, this option considers the outer shape of the island but does not support holes or concave features.

  • Concave: The slowest option, which uses the actual shape of the island for the most accurate pack.

Pack To#

The Pack To setting determines where your islands will be placed.

  • Closest UDIM: Places the island within the nearest UDIM.

  • Active UDIM: Packs the island into the currently active UDIM.

  • Bounding Box: Packs the island based on its bounding box before packing.

If UDIMs are not in use, the first two options will pack all islands into the default UV space (0 to 1).

Transform#

Merge Overlapping allows overlapping islands to be packed as a single island. This is particularly useful when duplicated or mirrored UVs are laid directly on top of each other.

Lock Pinned controls how much your pinned UV islands are transformed during packing. This ensures that important UVs remain in place while others are adjusted.

Average Scale applies an Average Island Scale operation to all UV islands before packing, ensuring that they share the same texel density.

Rotation determines how much each island is allowed to rotate during packing.

  • Full Rotation: Allows islands to rotate freely, resulting in a tighter pack but potentially skewed islands.

  • Cardinal: Restricts rotation to 90-degree increments.

  • Axis Aligned: Rotates islands to fit the smallest possible vertical or horizontal bounding box.

Scale controls how the islands are scaled before packing.

  • None: Does not scale the islands at all before packing, which is helpful when your islands are already at a set texel density or real world scale.

  • Fit: Scales the islands so that the resulting pack fits exactly inside the UV space.

  • Average and Fit: Averages the scale of each island so they all have the same texel density before scaling them to fit inside the UV space.

Margin#

Margin Amount controls the space between each UV island. It is recommended to maintain some margin to prevent pixel bleeding between islands. For applications that support Mip Mapping (e.g., most game engines), a margin of at least 1.6% is advised.

  • Fast Method: Quick to compute but provides a rough approximation.

  • Exact Method: Slower but ensures pixel-perfect padding.

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