Point Attributes

Point Attributes are Attributes on Points in a SOP.

Normally items are located spatially by XYZ values. To differentiate texture coordinate space from XYZ space, the labels U and V are used instead of X and Y.

In order to place texture maps (images) onto geometry, we must assign texture coordinates to the geometry. A texture map resides in its own (U, V) texture coordinate space. When assigned to the geometry, the (U, V) coordinates designate how to map the image onto the geometry. Texture space should not be mistaken for the parametric space of splines.

You can use the Texture SOP, Point SOP or the SOP to DAT with the DAT to SOP pairs to add or modify these attributes.

Texture coordinates can be visualized in the following manner: Texture maps have their own coordinate space. If the texture were a table cloth with a grid pattern, the color at location 3, 4 on the table cloth remains at location 3, 4 even when the cloth is wrapped around an irregularly shaped object. The color at location 3, 4 can be said to be in the table-cloth's coordinate space.

TIP: By using a Point SOP, you can swap the position and the texture coordinates. This allows you to model the "texture space". Another Point SOP allows you to swap the position and texture back to their original locations.

Point Attributes

Name	Type	Size	Description
P	float	3	Point position
Pw	float	1	Point weight
N	vector	3	Surface normal
uv	float	3	Texture coordinates
Cd	float	4	Surface color and alpha
v	vector	3	Velocity
mass	float	1	Mass
drag	float	1	Drag
tension	float	1	Tension
springk	float	1	Spring constant
up	vector	3	Up
pscale	float	1	Particle scale
radiusf	float	1	Radius
scalef	float	1	Force scale
radialf	float	1	Radial force
normalf	float	1	Normal force
edgef	float	1	Edge force
edge_dir	vector	3	Edge direction
dirf	vector	3	Directional force
pCapt	float	2	Capture data containing index and weight for a transform. See Deforming Geometry (Skinning)

Attributes are data associated with POP geometry. Points, Vertex (Vertices) and Primitives (polygons, lines, etc) can have any number of attributes.

A Operator Family that reads, creates and modifies 3D points, polygons, lines, particles, surfaces, spheres and meatballs. Particles and point clouds are now done primarily on the GPU using TOPs.