Houdini 20.0 Nodes Geometry nodes

Sculpt geometry node

Lets you interactively reshape a surface by brushing.

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Using Sculpt

  1. Select the object you want to sculpt, or in component mode, select a subset of the points in an object.

    When you select a subset of points, the Sculpt tool will only be able to modify the selected points. The unselected points will be protected from brushing.

  2. Click the Sculpt tool on the Model tab.

  3. Do any of the following:

    • Shift-drag to change the size of the brush, or use the Radius control on the operation toolbar (across the top of the viewer).

    • Right click to assign operations to LMB and MMB, change the brush shape, and set other options.

    • FD on the toolbar controls the amount of displacement caused by brushing with LMB. BD controls the amount caused by brushing with MMB. These are the same as the parameters in the LMB Displacement and MMB Displacement sub-tabs of the Operation tab in the parameter editor.

    • Opacity controls how much deformation or smoothing the tool will do with each brush-stroke. This is the same as the Opacity parameter on the Brush tab in the parameter editor.

    • Drag across the surface with LMB or MMB to perform the assigned operation on the selected points.

Tip

The brush casts through the surface and sometimes you may find that strokes on the surface deform points on the opposite side of the surface.

You can minimize this by enabling the Depth parameter on the Brush tab in the parameter editor. The Depth values limit how far above and below the surface the brush will cast.

You can copy the Radius parameter and paste it as a relative reference into both Depth fields to create a spherical/cubical (depending on brush shape) brush. This is usually sufficient to eliminate problems casting through, unless you are using a large brush size.

Parameters

Operation

Goal

Deform Points

Moves each point along its normal.

Smooth Points

Moves each point towards the average of its neighbors. This is a per dab operation, thus does not accumulate a stencil buffer.

Deform and Smooth

Applies both the deformation and a smoothing pass.

Axis, Vector

Determine what direction the deformation occurs in. “Normal” refers to the surface normal at the point; the others are in the object’s coordinates.

Accumulate To Stencil

By default, the operation is applied and the stencil cleared after every brush stroke. With this set, the stencil is not cleared until “Apply and Clear Stencil” is pressed.

Apply & Clear Stencil

Applies the operation and clears the stencil. This is equivalent to right-clicking in the viewport.

Update Displacement Normals

Recomputes the point normals used by the sculpting operation.

LMB/MMB Displacements (FD/BD)

Specify the amount by which to displace the surface. If “Accumulate To Stencil” is on, the left mouse does foreground and the middle mouse erases.

Apply To All

Deforms all of the selected geometry.

Reset All Changes

Restores geometry to initial state.

Brush

Shape

The basic shape of the brush: circle, square, or bitmap.

Bitmap

What bitmap to use. The alpha channel becomes the brush.

Radius

The radius of the brush when painting in the 3d viewport.

UV Radius

The radius of the brush when painting in the 2d viewport.

Radius Pressure

This controls how much effect the pressure of a stylus will have on the radius. A value of 1 means the radius will go from 0 to the amount in Radius. A value of 0 will mean the radius will always be constant, regardless of pressure. A value of 0.5 will mean the radius will be scaled between one half of Radius and Radius.

Depth

If set, this limits how far the brush will paint along its axis. This can be used if connectivity is disabled to limit the effect of the brush. The first parameter is how deep below the surface the brush should penetrate. The second is how high above the surface it should stop. These values can be negative.

Brush Angle

How far to rotate the brush.

Brush Squash

Amount to squash the brush in the y direction before rotation.

Opacity

The amount to affect the stencil mask.

Opacity Pressure

This controls the how much effect the pressure of a stylus will have on the opacity. It obeys the same scaling as the Radius Pressure.

Brush Splatter

A random noise in the brush’s opacity based upon the position on the brush.

Paper Grain

A random noise on the object’s stencil mask based on the object position.

Soft Edge

Percentage of the brush to be rolled off.

Kernel Function

Which metaball kernel to use for the roll off.

Up Vector Type

How the brush should be oriented on the surface:

Stroke Direction

Oriented in the direction in which the brush moves.

Fixed

Oriented as specified in the Up Vector field.

Up Vector

The fixed up vector to orient brush to.

Symmetry

Reflective

If set, the brush will perform reflective symmetry. Any strokes will be mirrored along the plane of symmetry.

Rotational

If set, the brush will perform rotational symmetry. Any strokes will be rotated around the axis of symmetry.

Axis

This defines the normal of the plane of symmetry for reflection and the axis of symmetry for rotation.

Origin

This defines the origin of the plane of symmetry for reflection and the origin of the axis of symmetry for rotation.

Number of Rotate

This defines the degree of rotational symmetry. A degree of 3 means the stroke will be applied 3 times at 120 degree separation. A value of 5 will perform the stroke 5 times with 72 degrees of separation.

Reflection Dist

This is the distance of the plane of symmetry from the origin of symmetry.

UV Reflective

If set, the brush will reflect when brushing is done in the UV viewport.

UV Origin

The origin of the line of reflection in the UV viewport.

UV Angle

The angle of the line of reflection in the UV viewport. 0 will mirror about the U axis, 90 will mirror about the V axis.

Stroke

Orient Brush To Surface

Switches between the brush being perpendicular to the surface or always oriented along the view direction. If you are having trouble with a shaky brush, try turning this off. Turn this off in order to brush on disconnected points, (point clouds).

Use Connectivity

If set, the tool will only affect points connected to the closest point to the intersection. This is usually a good thing, as it avoids accidentally painting through the geometry (but see the depth parameter), but can prevent smoothly painting across seams. This should usually be turned off in order to brush on disconnected points, (point clouds), since they are not connected to each other.

Use Normals

If set, the tool will only affect points facing in the same direction as the closet point to the intersection. This is usually good to avoid accidentally painting the backfacing parts of geometry, but if you want a pure depth brush can be turned off.

Realtime Mode

Set this to paint geometry as it’s deforming.

Direction

The current direction of the brush. If orient to surface is on, this is the normal direction of the surface hit by the brush. Otherwise, it is the direction from the eye to the surface.

Hit Location

The current location of the brush. This tracks the surface as the brush moves along it.

Hit Primitive

The primitive number of the primitive the current brush is centered at.

Hit UV

The location the current brush is on the current primitive. Note this is a parametric UV location, not the texture UV location.

Hit Pressure

The amount of force the brush is currently applying. This is only meaningful when a tablet interface that supports pressure is used.

Hit Point

The point closest to the current brush’s center.

Event

Controls the current state of the brush. When it is on No-op, the values of the stroke tab are ignored and no updating of the geometry is done. Other values are set automatically as you brush the surface, allowing the SOP to update in response to your actions.

See also

Geometry nodes