Modify existing strokes

Modify stroke settings for existing strokes

After painting a stroke, you can change the stroke settings defined for the Paint Effects Tool (display quality, surface offset, pressure mappings), but you can also change a number of other settings.

To modify stroke settings for an existing stroke

1. Select the stroke. For details, see Select strokes.
2. Do one of the following:
   • In the Attribute Editor, click the strokeShape tab and modify the settings.
   • In the Channel Box, click the strokeShape node (under SHAPES) and modify the settings.

   For descriptions of the strokeShape attributes, see strokeShape node.

   Tip

   To modify settings for several strokes at the same time (for example to change the Display Percent), select all the strokes (Edit > Select All by Type > Strokes), open the Attribute Spreadsheet, click the Shape Keyable tab, then modify the settings. For information on using the Attribute Spreadsheet to modify settings, see Modify brush settings for existing strokes.

Copy brush settings from existing strokes to the template brush

You can copy the brush settings of any stroke to the template brush. Once the settings are in the template brush, you can modify them before painting your next stroke, or apply them to other existing strokes.

To copy settings from a stroke to the template brush

1. Select the stroke you want to copy brush settings from.
2. Select Paint Effects > Get Settings from Selected Stroke. The brush settings are copied to the template brush.

Apply brush settings to strokes

You can apply brush settings to a stroke from an existing brush (one that is attached to another stroke), a brush preset, or the template brush.

When you apply brush settings to strokes, the brushes attached to each of the strokes remain unique, even though they have the same settings—changes to one do not affect any other. If you want the strokes to share the same brush, use the Paint Effects > Share One Brush option. For details, see Make strokes share the same brush.

To apply preset brush settings to the last stroke

1. In the Visor (Paint Effects > Get Brush), or on a shelf, click the brush preset with the settings you want to apply to the last painted stroke.
2. Modify brush attributes, if necessary (Paint Effects > Template Brush Settings or use the Ctrl-b (Linux and Windows) or Control-b (Mac OS X) hotkey combination). For information on modifying brush attributes, see Define template brush settings.
3. Select Paint Effects > Apply Settings to Last Stroke. The template brush settings are copied to the last painted stroke, replacing its current settings.

To apply preset brush settings to selected strokes

1. Select the strokes you want to apply brush settings to. For details, see Select strokes.
2. In the Visor (Paint Effects > Get Brush), or on a shelf, click the brush preset with the settings you want to apply to the selected strokes.
3. Modify brush attributes, if necessary (Paint Effects > Template Brush Settings). For information on modifying brush attributes, see Define template brush settings.
4. Select Paint Effects > Apply Settings to Selected Strokes. The template brush settings are copied to the selected strokes, replacing their current settings.

To copy settings from one stroke and apply them to another

1. Select the stroke you want to copy brush settings from.
2. Select Paint Effects > Get Settings from Selected Stroke. The brush settings are copied to the template brush.
3. Modify brush attributes, if necessary (Paint Effects > Template Brush Settings or use the Ctrl-b (Linux and Windows) or Control-b (Mac OS X) hotkey combination). For information on modifying brush attributes, see Define template brush settings.
4. Select the strokes you want to apply the template brush settings to.
5. Select Paint Effects > Apply Settings to Selected Strokes. The template brush settings are copied to the selected strokes, replacing their current settings.

Make strokes share the same brush

Although by default each stroke has a unique brush attached to it, you can force strokes to share a single brush. When strokes share a brush, any changes you make to the brush affect all the strokes that brush is attached to. This is particularly useful if you have many strokes sharing the same look and behavior, for example, the strokes used for hair on a head.

When you attempt to share a brush with several strokes, the stroke attached to that brush must have been the last stroke selected. (The stroke last selected is also called the primary selection object and highlights green by default.) For example, if you want to share the brush attached to strokeFern1 with strokeGrass2, strokeGrass3 and strokeGrass4, you must first select the three Grass strokes, then select strokeFern1.

To make strokes share the same brush

1. Select the strokes you want to share the same brush, but do not select the stroke with the brush you are sharing.
2. Shift-click to select the stroke with the brush you are sharing. This ensures that it is the last selected stroke.
3. Select Paint Effects > Share One Brush. The strokes share the brush of the stroke selected last (the one selected in step #2).

   When you modify the attributes of this brush for any one stroke, the changes are reflected on all the strokes sharing that brush.

To remove brush sharing

1. Select the strokes you want to remove brush sharing from.
2. Select Paint Effects > Remove Brush Sharing.

   Paint Effects creates a new brush for each stroke using the settings of the shared brush. For example, if you remove brush sharing from three strokes sharing a brush named ferns1, the first created stroke retains the brush named ferns1, and new brushes named ferns2 and ferns3 are created and attached to the other two strokes.

Simplify stroke path curves

The stroke path is defined by an underlying stroke path curve which is comprised of CVs. Just like using the Pencil Curve Tool, painting a stroke can create irrelevant or too many CVs. You can simplify the curve by removing misplaced CVs, making the path through the CVs smoother.

Simplifying stroke path curves using the following method is not the same as rebuilding the curve. The following method attempts to preserve the appearance of the stroke and its tube, while the rebuilding method does not.

To simplify a stroke curve

1. Select the stroke.
2. Select Paint Effects > Curve Utilities > Simplify Stroke Path Curves.

To check that the stroke curve has few CVs

1. Select the stroke.
2. Show the underlying stroke path curve (select Display > Show > Show Geometry > Stroke Path Curves).
3. Select the stroke path curve. For details, see Define global scene settings.
4. Go into CV selection mode. For details, see Select curve CVs first last or all. Notice the number of CVs on the curve.
5. Hide the underlying stroke path curve (select Display > Hide > Hide Geometry > Stroke Path Curves).
6. Return to object selection mode.

Change the shape of a stroke

You can change the shape of Paint Effects strokes by transforming the CVs on the underlying stroke path curve.

To change the shape of a stroke

1. Select the stroke.
   
2. Show the underlying stroke path curve (select Display > Show > Show Geometry > Stroke Path Curves).
3. Select the stroke path curve.
4. Go into CV selection mode. For details, see “Limiting selection by component type” in the Basics guide.
5. Select the CVs and translate them.
   
6. Hide the underlying stroke path curve (select Display > Hide > Hide Geometry > Stroke Path Curves).
7. Return to object selection mode.
   

Modify stroke pressure values interactively

If you use a stylus with pressure mappings when you create a stroke, Paint Effects assigns pressure values to UV points on the underlying stroke path curve. These values are stored with the stroke. You can adjust each value individually in the Attribute Editor (see Modify pressure mappings for existing strokes), however, this could prove unwieldy given that strokes commonly have more than 100 pressure values.

Alternatively, you can interactively modify the pressure values using stroke pressure curves. A stroke pressure curve is a visual representation of the pressure values along the stroke. By moving control points of the pressure curve towards or away from a stroke, you change the pressure values on the stroke.

In the following example, Tube Length is mapped to pressure for the stroke. A pressure curve for the stroke was edited to produce new pressure values, and therefore new tube lengths.

To modify pressure values interactively

1. In the scene view, select the stroke.
2. Create the pressure curve as follows:
   • Select Paint Effects > Curve Utilities > Make Pressure Curve > . The Make Pressure Curve Options window appears.
   • Set how many control points you want along the pressure curve. The more control points, the smoother the transition between pressure points. Pressure points in between these points are linearly interpolated.
   • Set how far the pressure curve should be offset from the stroke. This has no effect on the pressure values—it just controls the position of the pressure curve, so you can set the scale according to your scene.
   • Click Create. Paint Effects creates the pressure curve on top of the stroke, then offsets the curve in a direction normal to the curve, based on the pressure values multiplied by the offset scale.

   An expression is also created when you create the curve.

3. Edit the pressure curve as follows:
   • Go into CV selection mode
   • Select CVs on the pressure curve and translate them to new pressure values. The distance of the pressure curve from the stroke in 3D affects the pressure values.
4. When you are satisfied with the new pressure values, you can remove the pressure curve. It is no longer needed.
   • Go back into component mode.
   • Select the pressure curve and delete it.

Erase, smear, and blur paint

You can erase, smear, and blur paint in your scene using any brush by setting the brush type to Erase, Smear or Blur, respectively. These brushes affect existing strokes using the shape of the brush you erase, smear, or blur with. For example, if the brush has leaves, the paint smears, blurs, or erases where the leaves are painted.

Erase brushes paint alpha values of 0. The stroke will appear black in the scene painting view and in the final render, which may not produce an erased effect. However, the stroke will create a “hole” in the alpha matte, which may be useful for some compositing workflows.

To erase, smear, or blur paint in the scene painting view

1. Switch to the scene painting view (press the 8 hotkey and select Paint > Paint Scene).
2. Do one of the following:
   • If you use a stylus and tablet, modify pressure mappings, if desired (Brush > Tool Settings). You can map up to three brush attributes to the stylus pressure. For information on modifying stylus pressure mappings, see Make the brush respond to stylus pressure.
   • If you want to ignore the pressure mappings, select Brush > Use Stylus Pressure to turn it off. You may want to ignore pressure mappings if you paint with a mouse rather than a stylus.
3. In the Visor (Brush > Get Brush), or on a shelf, click the brush preset you want to erase, smear, or blur with. The selected brush settings are copied to the template brush.
4. Select Brush > Tool Settings and turn on Paint at Depth.
5. Select Brush > Edit Template Brush. The Paint Effects Brush Settings window opens.
6. Beside Brush Type, select Erase, Smear, or Blur.
7. Under Channels, turn off Depth and make sure Force Depth on is turned off in the Paint Effects Globals.
8. Set Fake Shadows to None, if this is not already the setting.
9. Modify other template brush settings, if necessary. For information on modifying template brush settings, see Define template brush settings.
10. Drag across the area you want to erase, smear or blur.
    Tip

    Create some smear and blur type brush presets and save them on a shelf for easy access. For information on storing brushes, see Create new brush presets.