Particle Paint#

The Particle Paint tool allows you to paint and erase particles defined by a selected particle Container geometry. This tool only works in the 3D View.

(1) Particle Paint tool (2) Create particle Container script (3) Particle Paint cursor (4) particles display while painting (5) particles display after painting (6) Main Paint tool options (7) Brush options (8) Snapping and projection options (9) Particle properties options.

To paint particles, select a particle Container and then click-drag in the view to add new particles.

• Particles can be painted in empty space or directly on the items of the scene.
• Particles are always projected through the current view to the surface of the scene items.

Particles are projected to the underlying geometry and the brush cursor indicate the normal of the surface

To select a particle container in the scene using the 3D View, hold Ctrl key and Left Button 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 this tool is defined using the Paint Mode and the Tool Type options.

Paint Mode#

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

Tool Type#

Tool Type defines the type of the tool which can be an Airbrush, Paintbrush, Snapper, or an Eraser.

You can switch quickly between a brush tool and the erase tool by right-clicking in the 3D View and choosing the appropriate tool type from the contextual menu.

Alternately, you can use the Ins key to switch tool types. From the contextual menu, you can also remove all particles from the selected particle Container by selecting Clear Cloud.

Other options like Picking Precision, Display Path and Display Properties allows you to control the tool and the visual feedback:

Painting particles with Display Path enabled. Note: the path stays displayed until the next stroke is started.

Painting particles with Display Properties enabled. Here surface normals are displayed.

Mouse and Tablet Inputs#

To paint or erase particles, you can either use mouse or tablet input. More options are available using tablet input as pen pressure can be mapped to control density and size.

Pressure mapping applies both in paint and eraser tool types, but the effects are different. Please see sections Brush and Eraser 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.

Brush#

Brush options apply both to Airbrush and Paintbrush modes. 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:

Particles are created differently, depending on the type of brush.

Particles creation based on Brush Type

Sphere and Hemisphere brushes fill 3D volumes with particles whereas Flat Disk, Projected Disk and View fill 2D surfaces around the brush center.

Projected Disk and View brushes project each particle on scene geometry. If no geometry is intersected, the particles are projected onto the plane defined by the Snap Default Plane option.

(1) Sphere: particles are created inside a sphere around the intersection of the brush with the scene geometry.

(2) Flat Disk: particles are created inside a disk around the intersection of the brush with the scene geometry.

(3) Hemisphere: particles are created inside the upper hemisphere (defined by the normal of the hit surface) around the intersection of the brush with the scene geometry.

(4) Projected Disk: particles are created inside the disk around the intersection of the brush with the scene geometry. Each particle is projected onto the scene geometry.

(5) View: particles are created inside the disk in screen space. Each particle is projected onto the scene geometry.

In addition to Brush Type, you can use the following attributes to setup the brush tool:

Particle spread with no falloff and the default curve profile.

Particle spread with 100% falloff.

Note the profile curve is not read as falloff > 0.0%.

Particle spread with a curve profile.

Note the curve is used because falloff is set to 0.0%

When using a tablet, you can map the pen pressure to drive density and size:

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).

Eraser#

You can delete particles using the Eraser tool of the Particle Paint. To set the tool as eraser, either:

(1) set the Tool Type option to Eraser or (2) Right Button in the 3D View, with the Particle Paint tool activated, and select Erase, or (3) press the Ins key in 3D View with the Particle Paint tool activated.

Particle cloud before erasing

Particle cloud display while erasing ?

Particle cloud after erasing

When the tool is set to Eraser, the tool cursor will change its display.

Eraser cursor in View unit mode

Eraser cursor in World unit mode

The shape of the Eraser tool is defined using the Eraser 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 are decimated with respect to the Strength option.

You can control the Eraser tool using the following options:

Like Airbrush and Paintbrush tools, the Eraser supports option presets (use Save Eraser and Load Eraser buttons).

You can also map pen pressure to control the eraser, using the Eraser Pressure Mapping:

Snapping#

While painting, Clarisse will compute which piece of geometry is currently under mouse, and the brush center will snap onto it. Then particles will be generated within the brush (their location depending on the brush shape). The following options allow you to specify the target items that can receive particles:

When erasing, by default the eraser is snapped to the nearest particle found in the currently edited cloud. Hold the S key while erasing will snap the eraser onto the hit geometry rather than the nearest particle. This allows for example to decimate some particles lying on a background plane, keeping the front ones unchanged.

Clarisse also provides the Snapper which is a dedicated Tool Type used to snap existing particles to the geometries of the scene.

Snapper#

The Snapper allows you to snap particles to the surface of underlying geometries. It is very useful when you need to snap existing set of particles onto a geometry that has changed or to a completely new one.

With the default settings, particles within brush strokes get projected from their current position to the underlying geometry using the direction the view is currently looking at.

When no underlying surfaces/geometries are facing selected particles, no changes occur to the particles. However, Snapper is pretty comprehensive since it provides many modes and options controlling its behavior.

Update Normals#

When enabled, snapped particles will update their normals according to the surface normal of the new geometry they are snapped to. This is very handy if the particles are used in a scatterer setup with Use Support Normal on.

Original particles driving a scatterer using Support Normals

Particles snapped to the ground (note the updated normals)

Snapping Projection Mode#

Snapping Projection Mode controls how particles are projected to underlying geometries. Depending on your needs, there are multiple projection modes available:

Snapping Direction#

It is possible to set the direction of projection using Snapping Direction which can be either Forward, Backward or in Both directions.

Snapping Distance#

To perform snapping, particles are projected using rays that eventually end up intersecting a geometry of the scene. Using Min and Max Snapping Distance, it is possible to limit the minimum and maximum distance (in world space) from which intersections are taken into account.

This way, any geometries that located below the minimum and beyond the maximum distances get ignored. This feature is very useful to restrict the projection to a specific range in the scene.

Snapper Type#

The Snapper Type option allows you to control the shape of the Snapper brush used to select particles that will be projected to the scene. When clicking and dragging, particles within the brush gets selected.

In addition to Snapper Type, you can use the following attributes to setup the brush:

Snapper Weight#

By default, particles are snapped to the surface of the underlying geometry. Using the Snap Strength you control how far particles move away from their original position to the new snapped one in such way that when:

• at 0% particles don't move, keeping their original positions.
• at 100% particles stick to the underlying geometry surface.
• at 50% particles are half way between their original and their new snapped positions.

Particle Properties#

Particles that are stamped or sketched are added to current cloud as 3D positions. You may also add their 3D normals (computed as normal to the hit surface at brush location), or other properties directly related to the particle generation by the brush.

Here is the list of properties than can be bound to the particles while creating them:

Properties can be displayed in 3D View while painting the particles. To enabled property display, you must check the Display Properties option in the General tab.

Displaying surface normal while painting particles

Displaying brush orientation while painting particles

Displaying path direction while painting particles

Displaying particle rotation while painting particles