# Prim Class

A Prim describes an instance to a single geometry primitive. They are accessible through the SOP.prims member.

## Members[edit]

`center`

→ `tdu.Position`

:

Get or set the barycentric coordinate of this primitive. It is expressed as a tdu.Position object.

`index`

→ `int`

**(Read Only)**:

The primitive index in the list.

`normal`

→ `tdu.Vector`

**(Read Only)**:

The calculated normal vector of this primitive, expressed as a tdu.Vector object.

`owner`

→ `OP`

**(Read Only)**:

The OP to which this object belongs.

`weight`

→ `float`

**(Read Only)**:

The associated weight of the primitive. Only certain primitives, such as those created by the Metaball SOP can modify this value from its default of 2.0.

`direction`

→ `tdu.Vector`

**(Read Only)**:

A normalized vector pointing from the centroid of the SOP to the centroid of this primitive.

`min`

→ `tdu.Position`

**(Read Only)**:

The minimum coordinates of this primitive along each dimension, expressed as a tdu.Position object.

`max`

→ `tdu.Position`

**(Read Only)**:

The maximum coordinates of this primitive along each dimension, expressed as a tdu.Position object.

`size`

→ `tdu.Position`

**(Read Only)**:

The size of this primitive along each dimension, expressed as a tdu.Position object.

## Methods[edit]

`destroy(destroyPoints=True)`

→ `None`

:

Destroy and remove the actual primitive this object refers to. This operation is only valid when the primitive belongs to a scriptSOP. Note: after this call, other existing Prim objects in this SOP may no longer be valid.

- destroyPoints - (Keyword, Optional) If True, its points are destroyed as well, if false, they are simply detached. The argument is True by default.

`eval(u, v)`

→ `td.Position`

:

Evaluate the position on the primitive given the u,v coordinates. u,v should be in the range [0,1].

Note:Polygons and curves ignore the v parameter.center = op('box1').prim[0].eval(0.5, 0.5)

### Special Functions[edit]

`len(Prim)`

→ `int`

:

Returns the total number of vertices.

a = len(op('box1').prim[0])

`[index]`

→ `td.Vertex`

:

Get specific vertex given an integer index

n = op('box1').prims[5][0]

`[row, col]`

→ `td.Vertex`

:

Get specific vertex from a Mesh given integer row and column values.

v = op('grid1').prims[2,3]

`Iterator`

→ `td.Vertex`

:

Iterate over each vertex.

for m in op('box1').prims[5]: # do something with m, which is a Vertex

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