Line Art Modifier

The Line Art modifier generates stylized line art from the scene or selected source collection or objects.

Note

Due to lack of global cache at the moment, each Line Art modifier will run the entire occlusion calculation for itself. So if you have multiple line art modifiers to select different parts of the scene (to apply different styles, etc.), the evaluation will take much longer. There are plans to remedy this in the future, but this is a known limitation for now.

Options

../../../_images/grease-pencil_modifiers_generate_line-art_panel.png

The Line Art modifier.

Use Cache

Optimize rendering by using cached scene data from the first line art modifier in the stack. This option has the disadvantage of certain settings becoming unavailable.

This option only available when you have more than one Line Art modifier is the same modifier stack and the modifier is not the first Line Art modifier in the stack.

Source Type

What type of geometry source should line art be generated from.

Scene, Collection, Object

Object/Collection

Based on the source type, collection or object can be selected as source geometry.

Invert Collection Filtering

Select everything except lines from specified collection.

Note

Line Art will still load and calculate the entire visible scene to produce correct occlusion result, unless specified to do otherwise in object or collection Line Art Usage property.

Layer

The Grease Pencil Layers to put the result in.

Material

The Grease Pencil Materials to generate strokes with.

Geometry Processing

Custom Camera

Use custom camera instead of the active camera for calculating strokes. Useful when baking multiple shots in different angle as well as for motion graphics effects.

Remove Doubles

Perform a “merge by distance” operation when loading geometry into Line Art. The threshold of this operation is internally set to a value that is optimal for Line Art algorithm precision.

Overlapping Edges as Contour

This option allows overlapping edges (e.g. from an Edge Split modifier or imported geometry where two edges occupy the exact same space) to be drawn as contour. Enabling this option will slow down the calculation slightly but it will handle edge overlapping cases without erroneous occlusion results.

Instanced Objects

This option enables particles and other instanced objects to be loaded for line art calculation. There will be performance impact when there are a large amount of instanced objects in the scene.

Clipping Boundaries

When enabled, line art will generate clipping lines as contour type at the place where near or far clipping planes cut the model. Otherwise there will be no lines.

Crease on Smooth

Allow crease edges to show inside smooth surfaces.

Crease on Sharp

Allow creases to show on sharp edges.

Force Backface Culling

Remove all back faces to speed up calculation. Note, removing back faces will create edges in different occlusion levels than when disabled.

Edge Types

Line Art can identify different edge types. Selected edge types will be included in the result.

Contour

Where the edge becomes the separation line of front/backfacing faces.

Loose

Generate strokes for edges that do not form a Face.

Material Borders

Where the edge separates faces with different materials.

Edge Marks

Freestyle edge marks.

Intersections

Intersection lines between faces.

Crease

Where the edge angle is small enough. Controlled by Crease Threshold property.

Crease Threshold

Edge angles that are smaller than this value will be treated as crease.

Allow Overlap

Allow an edge to have multiple overlapping types. This will create a separate stroke for each overlapping type.

Style

../../../_images/grease-pencil_modifiers_generate_line-art_style-panel.png

Style subpanel.

Thickness

The strokes generated by line art are given this thickness.

Opacity

The strokes generated by line art are given this Opacity.

Occlusion

../../../_images/grease-pencil_modifiers_generate_line-art_occlusion-panel.png

Occlusion subpanel.

Range

If enabled, the modifier will select lines that have an occlusion level between start and end values.

Level

Desired occlusion level to be selected as line art result. A value of 0 means visible lines (no occlusion). A value of 1 means selecting lines that have been occluded by exactly one layer of faces.

Material Mask

If enabled, Line Art will only select lines that are occluded by certain faces whose material have specific occlusion masks set.

Masks

To select edges that have been occluded by the selected Material Mask.

Exact Match

If enabled, only lines that are occluded with the exact mask bit combination will be selected. Otherwise, lines that have been occluded by any one of specified material masks will be selected.

../../../_images/grease-pencil_modifiers_generate_line-art_transparency-mask.png

Demonstration of the usage of material masks.

Intersection

Allows you to select edges that intersect between two collections.

Collection Mask

Mask bits to match from Collection Line Art properties.

Exact Match

Require matching all intersection masks instead of just one.

../../../_images/grease-pencil_modifiers_generate_line-art_collection-mask.png

Demonstration of the usage of collection masks.

Face Mark Filtering

../../../_images/grease-pencil_modifiers_generate_line-art_face-mark-filtering-panel.png

Face Mark Filtering subpanel.

Face Mark Filtering can be used to have manual control over which feature edges produce strokes by using Freestyle face marks.

Invert

Invert face mark filtering.

Boundaries

Filter feature lines based on face mark boundaries.

Keep Contour

Preserve contour lines while filtering.

../../../_images/grease-pencil_modifiers_generate_line-art_face-mark-filtering-example.png

Chaining

../../../_images/grease-pencil_modifiers_generate_line-art_chaining-panel.png

Chaining subpanel.

Chain
Intersection with Contour

Allows intersection lines to be chained together with contour lines.

Note

Enabling this option will lead to ambiguity in intersection edge types. Intersection lines that have not been able to chain with any nearby contour lines will remain as intersection lines.

All Lines

Enabling this option will cause all lines to have the type of contour and to be chained together.

Loose Edges

Allow floating Edges that do not form a face to be chained together.

Loose as Contour

Edges that do not form a face will be classified as contour lines.

Preserve Details

Instead of splitting at each occlusion change, keep small details from the initial chain. When details are not kept, will create a much smoother result.

Geometry Space

Use geometry distance for chaining instead of image space.

Image Threshold

Allow the end point of short segments to be chained together if the 2D image space distance between them are within the specified threshold.

Smooth Tolerance

The strength of smoothing applied on jagged chains.

Angle Splitting

Split a chain at sharp “turning” points specified by this angle.

Vertex Weight Transfer

../../../_images/grease-pencil_modifiers_generate_line-art_vertex-weight-panel.png

Vertex Weight Transfer subpanel.

Filter Source

If source mesh has vertex groups whose name starts with this text, then the vertex weight info will be transferred into weight groups in Grease Pencil strokes.

Match Output

Transfer the filtered object vertex weights into Grease Pencil weight groups with the same names as the filtered ones.

Target

If Match Output is off, then a target vertex group has to be specified. If there are multiple weight groups copied into target, then the highest weight value is copied into it.

Composition

../../../_images/grease-pencil_modifiers_generate_line-art_composition-panel.png

Composition subpanel.

Overscan

To optimize rendering, Blender only renders the strokes for edges of the object that are in the camera’s view. This optimization however, can result in strokes ending abruptly at the edge of the image.

This value prevents this error by adding a margin outside the camera’s view to continue computing strokes.

Image Boundary Trimming

Trim all stroke right at the boundary of image (including overscan region).

Depth Offset

Move strokes slightly towards the camera to avoid clipping while preserve depth for the viewport. This option is unavailable unless Show in Front is disabled.

Towards Custom Camera

Offset strokes towards selected camera (see Custom Camera above) instead of the active camera.

Bake

../../../_images/grease-pencil_modifiers_generate_line-art_baking-panel.png

Bake options.

Bake Line Art

Bakes Line Art strokes for active Grease Pencil object within the start, end frame range in scene. Bake Line Art (All) bakes all Grease Pencil objects that contains at least one Line Art modifier. After baking, baked Line Art modifiers will be deactivated automatically.

Clear Baked Line Art

Clears baked line art frames within the scene frame range for active Grease Pencil object. Clear Baked Line Art (All) applies the same operation for all Grease Pencil objects that contains at least one Line Art modifier.

Warning

If you have drawn anything manually in the frame range of where line art runs, this operation will also clear those strokes!

Continue without Clearing

Re-activate a specific Line Art modifier without clearing baked strokes. This is useful for working on multiple portions of frames separately.