vector ptransform(vector vec, matrix transform)
vector4 ptransform(vector4 vec, matrix transform)
Transforms the vector using the given transform matrix.
vector ptransform(string tospace, vector vec)
Transforms from "space:current".
vector ptransform(string fromspace, string tospace, vector vec)
Transforms the vector from fromspace into tospace.
fromspace, tospace
The possible values for the space arguments are:
An object path |
Use the object space of an object specified by a path string. Tip In some cases, such as point instancing, mantra may
automatically mangle object paths. You can generate an |
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Object space of the current object. |
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Object space of the current light when executing a shadow or light shader. |
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Houdini world space. |
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mantra camera space. |
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Normal Device Coordinate space. |
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Normal Device Coordinate space for the current light when executing a shadow or light shader. |
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The current space the vector is in. |
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Houdini world space. |
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ptransform interprets the vector as a position.
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vtransform interprets the vector as a direction vector, and so doesn’t apply the translations from the matrix.
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ntransform interprets the vector as a normal vector, and so multiplies by the inverse transpose of the matrix (ignoring the translations).
Examples
The version with only a tospace argument assumes fromspace is
"space:current". For example:
Pworld = ptransform("space:world", P);
…is equivalent to:
Pworld = ptransform("space:current", "space:world", P);
Transform a vector from its current space to object space:
ospace = ptransform("space:object", P)
Transform a vector from object space to mantra’s natural coordinate space ("camera" space):
ospace = ptransform("space:object", "space:current", P)
| See also | |
| point |
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| transform |
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