# Property Paint#

The Property Paint tool allows you to paint particle properties to a selected particle Container geometry. This tool only works in the 3D View. To paint particle properties, select a particle Container, choose the property name using the Name option in the Tool Options and then click-drag in the view to paint properties on existing particles.

Painting the values of a color property using the Property Paint tool

(1) Property Paint tool (2) property display of the current particle Container (3) Property Paint cursor (4) property display while painting (5) main tool options (6) property options (7) brush options.

Particle properties can either be created using the Particle Paint tool or using the Property Editor. With the Property Paint tool, you can edit any numeric properties like scalars, vectors (of any dimensions), colors, orientations...

To select a particle container in the scene using the 3D View hold Ctrl key and left-click on the Container you wish to select. Alternatively you can use the standard navigation widgets such as the Browser and the Explorer.

The behavior of the tool is defined using the Paint Mode and the Action options.

## Paint Mode#

Paint Mode defines the tool's interaction with the 3D View.

Paint Mode Description
Stamp Properties are edited on mouse up, while mouse drag modifies the stroke position.
Sketch (default) Properties are continuously edited while dragging the mouse. The stroke is validated on mouse up and using the Esc shortcut cancels the stroke.

## Action#

Action defines how the tool is acting on the particle property.

Action Description
Set (default) Property values are set to the same value defined in the Property tab.
Add Property values get added by the value defined in the Property tab.
Mult Property values get multiplied by the value defined in the Property tab.
Erase Property values are deleted resulting in a sparse property array.

You can switch quickly between the Erase action and the other actions (Set, Add, Mult) by right-clicking in the 3D View and choosing the appropriate action from the contextual menu.

Alternately, you can use the Ins shortcut to switch action. From the contextual menu, you can also pick a particle to display its property value. The property value is then printed in the Log.

Other options like Picking Precision and Display Path allows you to control the tool snapping onto particles and the visual feedback:

Option Description
Opacity Threshold Specifies the alpha level to ignore target objects that don't match that level during the snapping process.
Picking Precision Defines the distance threshold to pick a particle, in screen space.
Display Path When checked, the path of the brush is displayed over the current stroke.

## Mouse and Tablet Inputs#

To paint particle properties, you can either use mouse or tablet input. More options are available using tablet input as pen pressure can be mapped to control strength and size. Please see Brush section for more details on pen pressure mapping.

In Sketch mode, it is possible to continue the last stroke. Usually, when adding particles, a stroke is started on mouse down, and completed on mouse up.

Next mouse down will initiate a new stroke. You may append to previous stroke by pressing and holding Ctrl+Shift before mouse down. Particles are added to fill the gap between the end of previous stroke and the starting point of the current stroke.

This feature is available in Sketch mode only, as long as you don’t move the mouse outside the 3D View and keep the same viewpoint. It does not work with the Eraser tool.

Drag to edit particle properties.
Shift+ Drag to constrain the brush to an horizontal or vertical path. A grey guideline is drawn as long as the drag is constrained. Releasing the Shift key while dragging will release the constraint and allow a free path.
Shift+Ctrl+ Drag to continue last stroke (in Sketch mode only).
Ctrl+ Select particle Container.
Drag to increase or decrease brush size. While dragging, the size value is displayed in the brush cursor.
Shift+ Drag to increase or decrease brush strength. While dragging, the strength value is displayed in the brush cursor.
Ctrl+ Drag to increase or decrease brush strength falloff. While dragging, the falloff value is displayed in the brush cursor.
Eraser action Description
Drag to erase particles
Shift+ Drag to constrain the eraser to an horizontal or vertical path. A grey guideline is drawn as long as the drag is constrained. Releasing the Shift+ key while dragging will release the constraint and allow a free path.
Ctrl+ Select particle Container
++middle--button++ Drag to increase or decrease eraser size. While dragging, the size value is displayed in the eraser cursor.
Shift+ Drag to increase or decrease eraser strength. While dragging, the density value is displayed in the eraser cursor.
Ctrl+ Drag to increase or decrease eraser strength falloff. While dragging, the falloff value is displayed in the eraser cursor.

## Working with Properties#

To edit property values, you must specify which property you want to edit by choosing a property, among those available in the particle Container, via the Name option.

The Value option defines the value(s) used to alter the property value on selected particles. The number of sub-values depends on the property format (for example a color will need 3 values, a scalar weight only one).

When Add or Mult action is selected, the sub-value(s) format is float, even when the property is integer, so that any operation can be performed (clamping and rounding is performed internally). Default value is 0.0 for Add, 1.0 for Mult.

When Set action is selected, the sub-value(s) format match the property format (signed or unsigned integer or float). The Value option is disabled when the Erase action is chosen.

Tip

If the tool action is currently in Set mode, you can pick property values using the picking mode. The value will also be copied to the Value option of the Property options tab. Thus you can pick a value, paint it, pick another one, paint it, and so on, without typing any number.

The Display option defines the way property values are displayed in the 3D View while editing. The available choices depend on the property format. It’s up to you to pick the most appropriate feedback:

Property format Visual feedback
Properties with a single scalar value format Grey Level, Color ID, Number, Screen or World radius. Be careful, when the cloud is very dense, displaying the property as numbers may be very slow and anyhow unreadable. You may consider using Grey level or Color ID instead. Both radius modes draw circles around each particle, which is not appropriate either for dense clouds.
Properties with 3 numerical values format Screen or World Vector (draws value as is), Direction (draws normalized vectors), Orientation (considers property values as a rotations and draws a orientation axis on each particle), RGB (assumes value range is [0,255] for an integer property, [0,1] for a float one).
Properties with 4 numerical values format RGBA or Q Orientation (Clarisse then considers data as quaternions and provides the appropriate Mult action).

In addition to the previous display modes, you can you not to display the property values (choosing the None mode) or to hide the particle cloud itself (choosing Invisible mode). For instance, the Invisible mode is useful when the property is used to drive a scatterer and the scattered geometry provides enough feedback.

### Picking Property Values#

The Property Paint tool can be used also to inspect any particle property defined on any kind of cloud, but editing brushes will be disabled if the selected cloud is not editable.

In order to enter the Pick property mode, either in the 3D View and select the Pick Value entry in the contextual menu, or press P. In Pick mode, the tool cursor is displayed as a cross for precise particle selection. When picking a particle and the value for the current property is printed in the Log.

## Brush#

Brush options apply both to Set, Add and Mult actions. In the Property Paint tool, brushes act as a particle selector. Brush Type defines the shape of the brush. In all cases, the brush center is snapped onto the hit geometry (which may be the default plane).

Except in View mode, brushes are oriented with respect to the hit geometry's surface normal. If no geometry is hit, the surface normal is defined by the normal of the plane specified by the Snap Default Plane option. Particles are generated within the brush, in a 3D volume (Sphere, Hemisphere) or in a 2D area (Flat or Projected Disk) or in screen area (View). In the 3D View, the brush cursor changes shape according to the Brush Type:

Editing particle properties using the Property Paint tool

The shape of the tool is defined using the Brush Type option. In all cases except Punch mode, the brush center is snapped onto the hit geometry, which is usually the closest particle, or if snapping is activated, any piece of geometry in the scene.

When snapping is activated, Hemisphere and Cylinder brushes are aligned onto the hit surface normal, otherwise, they are aligned on the view normal. Particles that fall within the eraser have the current property removed with respect to the Strength option.

Eraser Type Description
Sphere Particles are selected within an oriented sphere in 3D space.
Cylinder Particles are selected within an oriented think disk in 3D space.
Hemisphere Particles are selected within an oriented half-sphere in 3D space.
Punch (View unit mode only) Particles are selected within an infinitely long cylinder perpendicular to the view plane.

You can control the tool using the following options:

Option Description
Brush Size Defines the diameter of the brush.
Brush Thickness Defines the height of the cylinder shape (used for Cylinder type only).
Brush Unit Defines in which space the brush is moving. In World space, the radius visually varies when you move the mouse around, whereas in Screen space, the radius visually remains the same. Therefore, in Screen space, you select more particles when you move the bursh farther. In World space, you select exactly the same number of particles, wherever to tool is located.
Brush Strength Modulates the number of particles that will be affected by the tool's Action.
Brush Falloff Control the strength profile. Higher values select more particles near the center of the brush.

Tip

When setting up your brush, you can pin the brush cursor inside the 3D View so that when editing its options, you will have visual feedback. To pin the brush cursor, move the cursor in the 3D View, then press the End key to freeze its position. You will now be able to preview any changes of the brush options. To free the brush cursor, press the End key again.

You can also map pen pressure to control the tool, using the Brush Pressure Mapping:

Brush Pressure Mapping Description
Strength Brush strength is controlled by pen pressure.
Size Brush size is controlled by pen pressure.
Strength + Size Both brush strength and size are controlled by pen pressure.
None Pen pressure has no effect on the tool.

Your brush settings can be saved as preset and loaded back using the Save Brush and Load Brush buttons. Note that the file used to store brush presets can be changed via Clarisse Preferences in (User Interface > Brush Presets File).

Brush Presets Description
Load Brush Select a brush among the available presets and load it as the current brush.
Save Brush Save the current brush settings as a preset. You will have to provide a name for the new preset.

## Eraser#

You can remove particle properties using the Eraser tool of the Property Paint. To set the tool as eraser, either (1) set the Action option to Erase, or (2) in the 3D View, with the Property Paint tool activated, and select Erase, or (3) press the Insert shortcut in 3D View with the Property Paint tool activated. When Action is set to Erase, the tool cursor will change its display.

Erasing particle properties using the Property Paint tool

The Eraser options behave exactly like Brush options but have different names. Eraser settings can be saved into presets and restored, and pen pressure can control the Eraser strength and/or its size.

Option Description
Eraser Type Defines the shape of the eraser.
Eraser Size Defines the diameter of the eraser.
Eraser Thickness Defines the height of the cylinder shape (used for Cylinder type only).
Eraser Unit Defines in which space the eraser is moving. In World space, the radius visually varies when you move the mouse around, whereas in Screen space, the radius visually remains the same. Therefore, in Screen space, you decimate more particles when you move the eraser farther. In World space, you decimate exactly the same number of particles, wherever to tool is located.
Eraser Strength Modulates the number of particles that will have the current property removed.
Eraser Falloff Control the eraser strength profile. Higher values affect more particles near the center of the eraser.
Eraser Pressure Mapping Define how pen pressure is used to control Eraser Strength and Eraser Size.