VEX function

* lerp

Performs bilinear interpolation between the values.

1. float lerp(float value1, float value2, float amount)

2. vector lerp(vector value1, vector value2, float amount)

3. vector4 lerp(vector4 value1, vector4 value2, float amount)

Performs bilinear interpolation between the values. If the amount is outside the range 0 to 1, the values will be extrapolated linearly.

* point

Imports a point attribute value from a geometry.

Overview

1. type point(string geometry, string attribute_name, int pointnumber)

2. type point(int opinput, string attribute_name, int pointnumber)

Returns 0 if importing the attribute failed, the value of the attribute on success.

geometry	The name of the geometry file to reference. Inside Houdini, this may be op:full_path_to_sop to reference a SOP.
attribute_name	The name of the attribute (i.e. Cd or P).
number	The point number.

Examples

vector        pos;
// Get the position of point 3 in "defgeo.bgeo"
pos = point("defgeo.bgeo", "P", 3);

* addvariablename

Adds the mapping of the attribute aname to the local variable vname.

1. void addvariablename(string aname, string vname)

Adds the mapping of the attribute aname to the local variable vname. In SOPs that support this, such as the Point SOP, one will then have the local variable $vname referencing the attribute aname. This emulates the behavior of the AttribCreate SOP.

ex) addvariablename("rot", "ROT");

* concat

Concatenate all the strings specified to form a single string.

1. string concat(string s1, string s2)

Concatenate all the strings specified to form a single string. This is equivalent (but slightly more efficient when there are more than 2 strings) to adding all the strings together.

ex) s@name = concat(chs("prefix"), "_", itoa(@primnum));

* itoa

Converts an integer to a string.

1. string itoa(int number)

Converts an integer to a string.

ex) itoa(@primnum)

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See VEX contexts to learn about the different contexts (such as surface shaders or displacement shaders) in which the various functions and statements are available.

Functions

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	Du	Takes the derivative of the given value with respect to U.
	Dv	Takes the derivative of the given value with respect to V.
	Dw	Takes the derivative of the given value with respect to the 3rd axis, for volume rendering.
	abs	Returns the absolute value of the argument.
	acos	Returns the arc-cosine of the argument.
	addattribute	Adds or changes a point attribute.
	addgroup	Adds the particle specified by point_number to the group specified.
	addpoint	Adds a point to the geometry.
	addprim	Adds a primitive to the geometry.
	addvariablename	Adds the mapping of the attribute aname to the local variable vname.
	addvertex	Adds a vertex to the geometry.
	albedo	Returns the albedo (percentage of reflected light) for a bsdf given the outgoing light direction.
	alphaname	Returns the default name of the alpha plane (as it appears in the compositor preferences).
	ambient	Returns the color of ambient light in the scene.
	anoise	These functions are similar to the Worley noise functions listed above.
	area	Returns the area of the micropolygon containing a variable such as P.
	array	Efficiently creates an array from its arguments.
	arraylength	Returns the length of an array.
	ashikhmin
	asin	Returns the arc-sine of the argument.
	assign	An efficient way of extracting the components of a vector, vector4, matrix3 or matrix to float variables.
	atan	Returns the arc-tangent of the argument.
	atan2	Returns the arc-tangent of y/x.
	atof	Converts a string to a float.
	atoi	Converts a string to an integer.
	atten	Computes attenuated falloff.
	attribsize	Returns the size of a geometry attribute.
	attribtype	Returns the type of a geometry attribute.
	avg	Returns the average of the vector’s 3 components
	binput	Returns bilinear sampled input.
	blinn	Returns the illumination for specular highlights using different lighting models.
	blinnBRDF
	bumpmap	Bump maps will return the color gradient of the image in the du/dv parameters.
	bumpmapA
	bumpmapB
	bumpmapG
	bumpmapL
	bumpmapR
	bumpname	Returns the default name of the bump plane (as it appears in the compositor preferences).
	ceil	Returns the smallest integer greater than or equal to the argument.
	ch	Evaluates a channel (or parameter) and return its value.
	ch3	Evaluates a channel (or parameter) and return its value.
	ch4	Evaluates a channel (or parameter) and return its value.
	chend	Returns the end sample of the input specified.
	chendf	Returns the frame corresponding to the last sample of the input specified.
	chendt	Returns the time corresponding to the last sample of the input specified.
	chf	Evaluates a channel (or parameter) and return its value.
	chi	Evaluates a channel (or parameter) and return its value.
	chinput	Returns the value of a channel at the specified sample in an input.
	chname	Returns the channel name of the indexed plane.
	chnumchan	Returns the number of channels in the input specified.
	chp	Evaluates a channel (or parameter) and return its value.
	chramp	Evaluates a ramp parameter and return its value.
	chrate	Returns the sample rate of the input specified.
	chs	Evaluates a channel (or parameter) and return its value.
	chstart	Returns the start sample of the input specified.
	chstartf	Returns the frame corresponding to the first sample of the input specified.
	chstartt	Returns the time corresponding to the first sample of the input specified.
	chv	Evaluates a channel (or parameter) and return its value.
	cinput	Returns point sampled input.
	ckspline	Computes a Catmull-Rom (Cardinal) spline between the key points specified.
	clamp	Returns value clamped between min and max.
	clip	Clip the line segment between p0 and p1.
	colormap	Looks up a color from a disk image.
	colorname	Returns the default name of the color plane (as it appears in the compositor preferences).
	computenormal	In the POP and SOP contexts, sets how/whether to recompute normals. In the shading contexts, computes normals.
	concat	Concatenate all the strings specified to form a single string.
	cone
	cos	Returns the cosine of the argument.
	cosh	Returns the hyperbolic cosine of the argument.
	cracktransform	Depending on the value of c, returns the translate (c=0), rotate (c=1), or scale (c=2) component of the transform (xform).
	cross	Returns the cross product between the two vectors.
	cspline	Computes a Catmull-Rom (Cardinal) spline between the key points specified.
	ctransform	Transforms between color spaces.
	cvex_bsdf
	degrees	Returns the argument from radians into degrees.
	depthmap	The depthmap functions work on an image which was rendered as a z-depth image from mantra.
	depthname	Returns the default name of the depth plane (as it appears in the compositor preferences).
	detail	Imports a detail attribute value from a geometry.
	detailattribsize	Returns the size of a geometry detail attribute.
	detailattribtype	Returns the type of a geometry detail attribute.
	determinant	Computes the determinant of the matrix.
	diffuse	Returns the diffuse (Lambertian) illumination given the normalized surface normal.
	diffuseBRDF
	dihedral	Computes the rotation matrix which rotates the vector a onto the vector b.
	dimport	Imports a variable from the displacement shader for the surface.
	distance	Returns the distance between the two 3 or 4 dimensional point arguments.
	distance2	Returns the squared distance between the two 3 or 4 dimensional point arguments.
	dot	Returns the dot product between the arguments.
	dsmpixel	Reads the z-records stored in a pixel of a deep shadow map or deep camera map.
	emission_bsdf	Returns the emissive component of a bsdf.
	environment	Returns the color of the environment texture.
	erf	Gauss error function.
	erfc	Gauss error function’s complement.
	eval_bsdf	Evaluates a bsdf given two vectors.
	exp	Returns the exponential function of the argument.
	fastshadow	Sends a ray from the position P along the direction specified by the direction D.
	filtershadow	Sends a ray from the position P along direction D.
	filterstep	Returns the anti-aliased weight of the step function.
	findattribval	Returns element index where an integer or string attribute has a certain value.
	findattribvalcount	Returns number of elements where an integer or string attribute has a certain value.
	finput	Returns fully filtered pixel input.
	fit	Takes the value in the range (omin, omax) and shifts it to the corresponding value in the new range (nmin, nmax).
	fit01	Takes the value in the range (0, 1) and shifts it to the corresponding value in the new range (nmin, nmax).
	fit10	Takes the value in the range (1, 0) and shifts it to the corresponding value in the new range (nmin, nmax).
	fit11	Takes the value in the range (-1, 1) and shifts it to the corresponding value in the new range (nmin, nmax).
	floor	Returns the largest integer less than or equal to the argument.
	flownoise	Generates 1D and 3D Perlin Flow Noise from 3D and 4D data.
	flowpnoise	There are two forms of Perlin-style noise: a non-periodic noise which changes randomly throughout N-dimensional space, and a periodic form which repeats over a given range of space.
	foreach
	forpoints
	frac	Returns the fractional component of the floating point number.
	fresnel	Computes the fresnel reflection/refraction contributions given an incoming vector, surface normal (both normalized), and an index of refraction (eta).
	fromNDC	Transforms a position from normal device coordinates to the coordinates in the appropriate space.
	frontface	If dot(I, Nref) is less than zero, N will be negated.
	gather	Sends rays into the scene and returns information from the shaders of surfaces hit by the rays.
	geoself	Returns a handle to the current geometry.
	getattribute	Copies the value of a geometry attribute into a variable.
	getbbox	Sets two vectors to the minimum and maximum corners of the bounding box for the entire geometry.
	getblurP	Returns the blurred point position (P) vector at a fractional time within the motion blur exposure.
	getbounces
	getbounds	Returns the bounding box of the geometry specified by the filename.
	getcomp	Extracts a single component of a vector type, matrix type, or array.
	getfogname	Returns the name of the current object whose shader is being run.
	getglobalraylevel	Returns the depth of the ray tree for computing global illumination.
	getlightname	Returns the name of the current light when called from within an illuminance loop, or converts an integer light ID into the light’s name.
	getlights	Returns an array of light identifiers for the currently shaded surface.
	getobjectname	Returns the name of the current object whose shader is being run.
	getphotonlight	Returns the integer ID of the light being used for photon shading.
	getraylevel	Returns the depth of the ray tree for the current shading.
	getrayweight	Returns an approximation to the contribution of the ray to the final pixel color.
	gradient	Returns the gradient of a field.
	gradient3d	Returns the gradient of a single channel texture image at the position specified by P.
	hasdetailattrib	Returns if a geometry detail attribute exists.
	hasplane	Returns 1 if the plane specified by the parameter exists in this COP.
	haspointattrib	Returns if a geometry point attribute exists.
	hasprimattrib	Returns if a geometry prim attribute exists.
	hasvertexattrib	Returns if a geometry vertex attribute exists.
	henyeygreenstein	Returns an anisotropic volumetric bsdf, which can scatter light forward or backward.
	hscript_noise	Mimics the Houdini expression functions noise(), snoise(), turb(), and sturb().
	hscript_rand	Produces the exact same results as the Houdini expression function of the same name.
	hscript_snoise
	hscript_sturb
	hscript_turb
	hsvtorgb	Convert HSV color space into RGB color space.
	iaspect	Returns the aspect ratio of the specified input.
	ichname	Returns the channel name of the indexed plane of the given input (e.
	ident	Computes identity matrices.
	iend	Returns the last frame of the specified input.
	iendtime	Returns the end time of the specified input.
	ihasplane	Returns 1 if the specified input has a plane named planename.
	illuminance	Loops through all light sources in the scene, calling the light shader for each light source to set the Cl and L global variables.
	import	Imports attribute data from the SOP or POP connected to the specified input.
	importance_light	Returns an estimate of a light’s contribution to the overall scene lighting.
	ingroup	Returns 1 if the particle specified by the point number is in the group specified by the string.
	inpointgroup	Returns 1 if the point specified by the point number is in the group specified by the string.
	inprimgroup	Returns 1 if the primitive specified by the primitive number is in the group specified by the string.
	instance	Creates an instance transform matrix.
	integrate3d	This function will “integrate” the 3d image along the line specified by p0 and p1.
	integrate3dClip	The integrate3dClip function integrates along the ray described by p0 and p1 where “interesting” things start happening in a given I3D texture.
	interpolate	Interpolates a value across the currently shaded micropolygon.
	intersect	This function computes the intersection of the specified ray with the geometry.
	intersect3d	This function intersects a ray (with it’s origin at p0 and extending to p1), against a 3d texture image.
	intersect_lights	Finds the nearest intersection of a ray with any of a list of (area) lights and runs the light shader at the intersection point.
	inumplanes	Returns the number of planes in the given input.
	invert	Inverts the matrix.
	iplaneindex	Returns the index of the plane named 'planename' in the specified input.
	iplanename	Returns the name of the plane specified by the planeindex of the given input (e.
	iplanesize	Returns the number of components in the plane named planename in the specified input.
	irate	Returns the frame rate of the specified input.
	irradiance	Computes irradiance (global illumination) at the point P with the normal N.
	isbound	Parameters in VEX can be overridden by geometry attributes (if the attributes exist on the surface being rendered).
	isconnected	Returns 1 if input_number is connected, or 0 if the input is not connected.
	isfogray	Returns 1 if the shader is being called to evaluate illumination for fog objects, or 0 if the light or shadow shader is being called to evaluate surface illumination.
	isframes	Returns 1 if the Vex CHOP’s Unit Menu is currently set to 'frames', 0 otherwise.
	isotropic	Returns an isotropic bsdf, which scatters light equally in all directions.
	israytracing	Indicates whether a shader is being executed for ray tracing.
	issamples	Returns 1 if the Vex CHOP’s Unit Menu is currently set to 'samples', 0 otherwise.
	isseconds	Returns 1 if the Vex CHOP’s Unit Menu is currently set to 'seconds', 0 otherwise.
	isshadowray	Returns 1 if the shader is being called to evaluate opacity for shadow rays, or 0 if the shader is being called to evaluate for surface color.
	istart	Returns the starting frame of the specified input.
	istarttime	Returns the start time of the specified input.
	isvarying	Check whether a VEX variable is varying or uniform.
	itoa	Converts an integer to a string.
	ixres	Returns the X resolution of the specified input.
	iyres	Returns the Y resolution of the specified input.
	kspline	Returns an interpolated value along a spline curve.
	length	Returns the length of the vector or vector4.
	length2	Returns the squared distance of the vector or vector4.
	lerp	Performs bilinear interpolation between the values.
	limport	Imports a variable from the light shader for the surface.
	lkspline	Computes a linear spline between the key points.
	log	Returns the natural logarithm of the argument.
	log10	Returns the logarithm (base 10) of the argument.
	lookat	Computes a rotation matrix to orient the z-axis along the vector (to-from) under the transformation.
	lspline	Computes a linear spline between the key points.
	luminance	Compute the luminance of the RGB color specified by the parameters.
	lumname	Returns the default name of the luminence plane (as it appears in the compositor preferences).
	maketransform	Builds a 3×3 or 4×4 transform matrix.
	maskname	Returns the default name of the mask plane (as it appears in the compositor preferences).
	match	This function returns 1 if the subject matches the pattern specified, or 0 if the subject doesn’t match.
	matchvex_blinn
	matchvex_specular
	mattrib	Returns the value of the point attribute for the metaballs if metaball geometry is specified to i3dgen.
	max
	mdensity	Returns the density of the metaball field if metaball geometry is specified to i3dgen.
	metaimport	Once you get a handle to a metaball using metastart and metanext, you can query attributes of the metaball with metaimport.
	metamarch	Takes the ray defined by p0 and p1 and partitions it into zero or more sub-intervals where each interval intersects a cluster of metaballs from filename.
	metanext
	metastart	Open a geometry file and return a “handle” for the metaballs of interest, at the position p.
	metaweight	Returns the metaweight of the geometry at position p.
	min
	minpos	Finds the closest position on the surface of a geometry.
	mspace	Transforms the position specified into the “local” space of the metaball.
	nbouncetypes
	nearpoint	Finds the closest point of a geometry.
	neighbour	Returns the point index of the neighbour of the point.
	neighbourcount	Returns the number of points that are connected to the specified point.
	neighbours	Returns an array of the point numbers of the neighbours of a point.
	newgroup	Creates a new group in which to put particles.
	newsampler
	nextsample
	ninput	Reads a pixel and its eight neighbors into a 3×3 matrix.
	noise	There are two forms of Perlin-style noise: a non-periodic noise which changes randomly throughout N-dimensional space, and a periodic form which repeats over a given range of space.
	normal_bsdf	Returns the normal for the diffuse component of a bsdf.
	normalize	Returns the normalized vector.
	normalname	Returns the default name of the normal plane (as it appears in the compositor preferences).
	npoints
	npointsgroup
	nprimitives	Returns the number of primitives in the geometry file.
	nprimitivesgroup
	nrandom	The nrandom() functions are non-deterministic random number generators for VEX.
	ntransform	See ptransform.
	nuniqueval	Returns the number of unique values from an integer or string attribute.
	occlusion	Computes ambient occlusion.
	onoise	These functions are similar to wnoise and vnoise.
	optransform	Returns the transform associated with an OP.
	ow_nspace	Transforms a normal vector from Object to World space.
	ow_space	Transforms a position value from Object to World space.
	ow_vspace	Transforms a direction vector from Object to World space.
	pathtrace
	pcclose	This function closes the handle associated with a pcopen function.
	pcconvex
	pcexport	Writes data to a point cloud inside a pciterate or a pcunshaded loop.
	pcfarthest	Returns the distance to the farthest point found in the search performed by pcopen.
	pcfilter	Filters the points found by pcopen using a simple reconstruction filter.
	pcgenerate	Generates a point cloud.
	pcimport	Imports channel data from a point cloud inside a pciterate or a pcunshaded loop.
	pciterate	This function can be used to iterate over all the points which were found in the pcopen query.
	pcnumfound	This node returns the number of points found by pcopen.
	pcopen	Returns a handle to a point cloud file.
	pcopenlod	Returns a handle to a point cloud file.
	pcsampleleaf	Changes the current iteration point to a leaf descendant of the current aggregate point.
	pcunshaded	Iterate over all of the points of a read-write channel which haven’t had any data written to the channel yet.
	pcwrite	Writes data to a point cloud file.
	phong	Returns the illumination for specular highlights using different lighting models.
	phongBRDF
	phonglobe
	photonmap	The photonmap function will evaluate a photon map and return the resulting color information.
	planeindex	Returns the index of the plane specified by the parameter, starting at zero.
	planename	Returns the name of the plane specified by the index (e.
	planesize	Returns the number of components in the plane (1 for scalar planes and up to 4 for vector planes).
	pluralize	Converts an English noun to its plural.
	pnoise	There are two forms of Perlin-style noise: a non-periodic noise which changes randomly throughout N-dimensional space, and a periodic form which repeats over a given range of space.
	point	Imports a point attribute value from a geometry.
	pointattribsize	Returns the size of a geometry point attribute.
	pointattribtype	Returns the type of a geometry point attribute.
	pointname	Returns the default name of the point plane (as it appears in the compositor preferences).
	pointvertex	Returns a linear vertex number of a point in a geometry.
	pop	Removes the last element of an array and returns it.
	pow	Raises the first argument to the power of the second argument.
	prim	Imports a primitive attribute value from a geometry.
	prim_attribute	Copies the value of a primitive attribute at a certain parametric (u, v) position into a variable.
	prim_normal	Returns the normal of the primitive (prim_number) at parametric location u, v.
	primattribsize	Returns the size of a geometry prim attribute.
	primattribtype	Returns the type of a geometry prim attribute.
	primintrinsic	Imports a primitive intrinsic from a geometry.
	primuv	Evaluates an attribute on a primitive at a certain parametric (u, v) position into a variable.
	primvertexcount	Returns number of vertices in a primitive in a geometry.
	printf	Prints values to the console which started the VEX program.
	ptlined	This function returns the closest distance between the point Q and a finite line segment between points P0 and P1.
	ptransform	Transforms a vector from one space to another.
	push	Adds an item to an array.
	qconvert	Converts a quaternion represented by a vector4 to a matrix3 representation.
	qdistance	Finds distance between two quaternions.
	qinvert	Inverts a quaternion rotation.
	qmultiply	Multiplies two quaternions and returns the result.
	qrotate	Rotates a vector by a quaternion.
	quaternion	Creates a vector4 representing a quaternion.
	radians	Converts the argument from degrees into radians.
	rand	Creates a random number between 0 and 1 from a seed.
	random	Generate a random number based on the position in N dimensional space (where N is 1 to 4 dimensions).
	random_sobol	Generate a uniformly distributed random number.
	rawbumpmap
	rawbumpmapA
	rawbumpmapB
	rawbumpmapG
	rawbumpmapL
	rawbumpmapR
	rawcolormap
	rayhittest	Sends a ray from the position P along the direction D.
	rayimport	Imports a value sent by a shader in a gather loop.
	reflect	Returns the vector representing the reflection of the direction against the normal.
	reflectlight	Computes the amount of reflected light which hits the surface.
	refract	Returns the refraction ray given an incoming direction, the normalized normal and an index of refraction.
	refractlight	Computes the illumination of surfaces refracted by the current surface.
	relbbox	Returns the relative position of the point given with respect to the bounding box of the entire geometry.
	removegroup	Removes the particle specified by point_number from the group specified.
	removepoint	Removes a point from the geometry.
	removeprim	Removes a primitive from the geometry.
	renderstate	Queries the renderer for a named property.
	resize	Sets the length of an array.
	resolvemissedray	Returns the background color for rays that exit the scene.
	rgbtohsv	Convert RGB color space to HSV color space.
	rint	Rounds the number to the closest integer.
	rotate	Applies a rotation to the given matrix.
	sample_bsdf	Samples a bsdf.
	sample_geometry	Samples geometry in the scene and returns information from the shaders of surfaces that were sampled.
	sample_light	Samples a 3D position on a light source and runs the light shader at that point.
	scale	Scales the given matrix in three directions simultaneously (X, Y, Z - given by the components of the scale_vector).
	serialize	Flattens an array of vector or matrix types into an array of floats.
	set	These two functions provide a very efficient way of creating a vector/vector4.
	setattrib	Sets an attribute in a geometry.
	setcomp	Sets a single component of a vector type, matrix type, or array.
	setcurrentlight	Sets the current light
	setdetailattrib	Sets a detail attribute in a geometry.
	setpointattrib	Sets a point attribute in a geometry.
	setpointgroup	Sets point group membership in a geometry.
	setprimattrib	Sets a primitive attribute in a geometry.
	setprimgroup	Sets primitive group membership in a geometry.
	setprimintrinsic	Sets a primitive intrinsic value in a geometry.
	setprimvertex	Rewires a vertex in the geometry.
	setvertexattrib	Sets a vertex attribute in a geometry.
	shadow	Calls shadow shaders for the current light source.
	shadow_light	Executes the shadow shader for a given light and returns the amount of shadowing as a multiplier of the shaded color.
	shadowmap	The shadowmap function will treat the shadow map as if the image were rendered from a light source.
	shimport	Imports a variable from the shadow shader for the surface.
	shl	Bit-shifts an integer left.
	shr	Bit-shifts an integer right.
	simport	Imports a variable sent by a surface shader in an illuminance loop.
	sin	Returns the sine of the argument.
	sinh	Returns the hyperbolic sine of the argument.
	sleep	Yields processing for a certain number of milliseconds.
	slerp	Quaternion blend between q1 and q2 based on the bias.
	smooth	Computes a number between zero and one.
	snoise	These functions are similar to wnoise.
	specular	Returns the illumination for specular highlights using different lighting models.
	specularBRDF	Returns the computed BRDFs for the different lighting models used in VEX shading.
	spline	Returns an interpolated value along a polyline or spline curve.
	split	Splits a string into tokens.
	sprintf	Formats a string like printf but returns the result as a string instead of printing it.
	sqrt	Returns the square root of the argument.
	storelightexport	Stores exported data for a light.
	strlen	Returns the length of the string.
	swizzle	Rearranges components of a vector.
	tan	Returns the trigonometric tangent of the argument
	tanh	Returns the hyperbolic tangent of the argument
	tet_adjacent	Returns primitive number of an adjacent tetrahedron.
	tet_faceindex	Returns vertex indices of each face of a tetrahedron.
	teximport	Imports attributes from texture files.
	texture	Computes a filtered sample of the texture map specified.
	texture3d	Returns the value of the 3d image at the position specified by P.
	texture3dBox	This function queries the 3D texture map specified and returns the bounding box information of the file.
	toNDC	Transforms a position into normal device coordinates.
	trace	Sends a ray from P along the normalized vector D.
	translate	Translates the given matrix.
	transpose	Transposes the given matrix.
	trunc	If the argument is negative, this returns ceil(x), otherwise it returns floor(x).
	tw_nspace	Transforms a normal vector from Texture to World space.
	tw_space	Transforms a position value from Texture to World space.
	tw_vspace	Transforms a direction vector from Texture to World space.
	uniqueval	Returns a unique value from an integer or string attribute.
	unserialize	Turns a flat array of floats into an array of vectors or matrices.
	variadicarguments
	velocityname	Returns the default name of the velocity plane (as it appears in the compositor preferences).
	vertex	Imports a vertex attribute value from a geometry.
	vertexattribsize	Returns the size of a geometry vertex attribute.
	vertexattribtype	Returns the type of a geometry vertex attribute.
	vertexindex	Convertex a primitive/vertex pair into a linear vertex.
	vertexnext	Returns the linear vertex number of next shared vertex in a geometry.
	vertexpoint	Returns the point number of linear vertex in a geometry.
	vertexprev	Returns the linear vertex number of previous shared vertex in a geometry.
	vertexprim	Returns the primitive number of a linear vertex in a geometry.
	vertexprimindex	Converts a linear vertex number into a vertex number within that primitive.
	vnoise	Voronoi noise gives almost identical results to the Worley noise functions.
	volume	Returns the volume of the microvoxel containing a variable such as P.
	volumegradient	Calculates the volume primitive’s gradient.
	volumeindex	Gets the value of a specific voxel.
	volumeindextopos	Converts a volume voxel index into a position.
	volumeindexv	Gets the vector value of a specific voxel.
	volumepostoindex	Converts a position into a volume voxel index.
	volumeres	Gets the resolution of a volume primitive.
	volumesample	Samples the volume primitive’s value.
	volumesamplev	Samples the volume primitive’s vector value.
	vtransform	See ptransform.
	wireblinn
	wirediffuse
	wnoise	Worley noise scatters points randomly through space (according to a nice Poisson distribution).
	wo_nspace	Transforms a normal vector from World to Object space.
	wo_space	Transforms a position value from World to Object space.
	wo_vspace	Transforms a direction vector from World to Object space.
	wt_nspace	Transforms a normal vector from World to Texture space.
	wt_space	Transforms a position value from World to Texture space.
	wt_vspace	Transforms a direction vector from World to Texture space.
	xyzdist	Finds the distance of a point to a geometry.