MaterialX Support

This page provides information on MaterialX (mtlx) support.

Overview

MaterialX is an open-source standard for representing shading networks. MaterialX shading networks can be used across different applications and renderers.

See the MaterialX and V-Ray blog post for more information.

Usage

V-Ray's implementation of MaterialX allows you to render MaterialX nodes encoded in USD with VRayScene-USD. The implementation is a mix of direct translation to V-Ray through a mapping file and custom code. Custom V-Ray plugins share the code and make graphs more efficient. The MaterialX graphs are rendered within Hydra.

Utilize the MaterialX nodes within the standard mtlx workflow in Solaris.

Workflow

Create MaterialX

Mtlx materials are created just like any other material in Solaris – inside a Material Library LOP.

Once the LOP is added, dive inside it and create a USD MaterialX Builder node. Inside the builder node, V-Ray supports most of the mtlx nodes (see the MaterialX Support table below for a full list of the supported nodes).

Then you just need to add an Assign Material LOP and specify a geometry for the mtlx materials. For more information on how to do it, see the Working with Solaris Materials page or watch the video in the Overview section.

Import MaterialX

To use premade mtlx files, use a Sublayer LOP to import them.

In the Sublayer LOP parameters, use the Add button to add as many sublayer files as there are mtlx files you want to import.

Then in the File paths of these sublayers, add the mtlx files.

The steps above only help you import the mtlx files in the scene. To assign the materials to geometry, add an Assign Material LOP and specify a geometry (path) for each mtlx material.

Reference MaterialX

Instead of adding sublayers of mtlx materials, you can reference them with a Reference LOP.

Set the Reference file to the file path of the mtlx file on disk, and select the specific material to load in through the Reference primitive submenu.

Then use an Assign Material LOP to assign the referenced mtlx material to a USD prim.

For more information about alternative workflows for referencing and creating mtlx materials, as well as information about the different types of mtlx nodes, refer to the Solaris documentation.

Supported Nodes

Category	MtlX Shader Name	Node Name	USD id	V-Ray Plugin
Adjustment	MtlX Adjust as HSV	mtlxhsvadjust	ND_hsvadjust
	MtlX Contrast	mtlxcontrast	ND_contrast	TexMayaContrast
	MtlX Curveadjust	mtlxcurveadjust	ND_curveadjust
	MtlX HSV to RGB	mtlxhsvtorgb	ND_hsvtorgb
	MtlX Luminance	mtlxluminance	ND_luminance	TexLuminance
	MtlX Range	mtlxrange	ND_range
	MtlX Remap	mtlxremap	ND_remap	TexSetRange / TexRemapFloat
	MtlX RGB to HSV	mtlxrgbtohsv	ND_rgbtohsv
	MtlX Saturate	mtlxsaturate	ND_saturate
	MtlX Smoothstep	mtlxsmoothstep	ND_smoothstep

Application	MtlX Frame	mtlxframe	ND_frame_float	TexSampler
Application	MtlX Time	mtlxtime	ND_time_float	multiple

Channel	MtlX Combine2	mtlxcombine2	ND_combine2
	MtlX Combine3	mtlxcombine3	ND_combine3	TexRgbaCombine
	MtlX Combine4	mtlxcombine4	ND_combine4	TexRgbaCombine
	MtlX Convert	mtlxconvert	ND_convert	multiple
	MtlX Extract	mtlxextract	ND_extract	TexAColorChannel
	MtlX Separate2	mtlxseparate2	ND_separate2
	MtlX Separate Color 3	mtlxseparate3c	ND_separate3	TexAColorOp
	MtlX Separate Vector 3	mtlxseparate3v	ND_separate3	TexAColorOp
	MtlX Separate Color 4	mtlxseparate4c	ND_separate4	TexAColorOp
	MtlX Separate Vector 4	mtlxseparate4v	ND_separate4	TexAColorOp
	MtlX Swizzle	mtlxswizzle	ND_swizzle

Compositing	MtlX Burn	mtlxburn	ND_burn	multiple
	MtlX Difference	mtlxdifference	ND_difference	multiple
	MtlX Disjoint Over	mtlxdisjointover	ND_disjointover	multiple
	MtlX Dodge	mtlxdodge	ND_dodge	multiple
	MtlX In	mtlxin	ND_in	multiple
	MtlX Inside	mtlxinside	ND_inside	TexMaskMax
	MtlX Mask	mtlxmask	ND_mask	multiple
	MtlX Matte	mtlxmatte	ND_matte	multiple
	MtlX Minus	mtlxminus	ND_minus	multiple
	MtlX Mix	mtlxmix	ND_mix	TexMix
	MtlX Out	mtlxout	ND_out	multiple
	MtlX Outside	mtlxoutside	ND_outside	TexMaskMax
	MtlX Over	mtlxover	ND_over	multiple
	MtlX Overlay	mtlxoverlay	ND_overlay	multiple
	MtlX Plus	mtlxplus	ND_plus	multiple
	MtlX Premult	mtlxpremult	ND_premult
	MtlX Screen	mtlxscreen	ND_screen	multiple
	MtlX Un-Premult	mtlxunpremult	ND_unpremult

Conditional	MtlX If Equal	mtlxifequal	ND_ifequal	TexCondition2
	MtlX If Greater	mtlxifgreater	ND_ifgreater	TexCondition2
	MtlX If Greater or Equal	mtlxifgreatereq	ND_ifgreatereq	TexCondition2
	MtlX Switch	mtlxswitch	ND_switch	TexMulti

Convolution2D	MtlX Blur	mtlxblur
Convolution2D	MtlX Height to Normal	mtlxheighttonormal	ND_heighttonormal

Geometric	MtlX Bitangent	mtlxbitangent	ND_bitangent
	MtlX Geometry Color	mtlxgeomcolor	ND_geomcolor	TexUserColor
	MtlX Geometry Property Value	mtlxgeompropvalue	ND_geompropvalue	multiple
	MtlX Normal	mtlxnormal	ND_normal_vector3	TexSampler
	MtlX Position	mtlxposition	ND_position_vector3	TexSampler
	MtlX Tangent	mtlxtangent	ND_tangent_vector3
	MtlX Texcoord	mtlxtexcoord	ND_texcoord_vector3

Global	MtlX Ambient Occlusion	mtlxambientocclusion	ND_ambientocclusion_float	TexDirt

Houdini	MtlX Bias	hmtlxbias	ND_hmtlxbias_float
	MtlX Facing Ratio	hmtlxfacingratio	ND_hmtlxfacingratio_float
	MtlX Gain	hmtlxgain	ND_hmtlxgain_float
	MtlX Hcatmullrom	hmtlxhcatmullrom	ND_hcatmullrom
	MtlX Hinvlinear	hmtlxhinvlinear	ND_hinvlinear_float
	MtlX Huniformcubic	hmtlxhuniformcubic	ND_huniformcubic
	MtlX Huniformramp	hmtlxhuniformramp	ND_huniformramp

Light	MtlX Directional Light	mtlxdirectional_light
	MtlX Point Light	mtlxpoint_light
	MtlX Spot Light	mtlxspot_light

Material	MtlX Surface Material	mtlxsurfacematerial
Material	MtlX Volume Material	mtlxvolumematerial

Procedural	MtlX Color Cubic Ramp	hmtlxcubicrampc		multiple
	MtlX Color Ramp	hmtlxrampc		multiple
	MtlX Constant	mtlxconstant	ND_constant	multiple
	MtlX Float Cubic Ramp	hmtlxcubicrampf		multiple
	MtlX Float Ramp	hmtlxrampf		multiple

Procedural2D	MtlX Cell Noise 2D	mtlxcellnoise2d	ND_cellnoise2d_float	multiple
	MtlX Noise2D	mtlxnoise2d	ND_noise2d	TexNoiseMaya
	MtlX Ramp4	mtlxramp4	ND_ramp4	TexRamp
	MtlX Ramplr	mtlxramplr	ND_ramplr	TexRamp
	MtlX Ramptb	mtlxramptb	ND_ramptb	TexRamp
	MtlX Splitlr	mtlxsplitlr	ND_splitlr
	MtlX Splittb	mtlxsplittb	ND_splittb
	MtlX Worley Noise 2D	mtlxworleynoise2d	ND_worleynoise2d

Procedural3D	MtlX Cell Noise 3D	mtlxcellnoise3d	ND_cellnoise3d_float	multiple
	MtlX Fractal3D	mtlxfractal3d	ND_fractal3d
	MtlX Noise3D	mtlxnoise3d	ND_noise3d
	MtlX Worley Noise 3D	mtlxworleynoise3d	ND_worleynoise3d

Texture2D	MtlX Image	mtlximage	ND_image	multiple
Texture2D	MtlX Tiled Image	mtlxtiledimage	ND_tiledimage	multiple

Texture3D	MtlX Triplanar Projection	mtlxtriplanarprojection	ND_triplanarprojection

Math	MtlX Absval	mtlxabsval	ND_absval	TexFloatOp / TexAColorOp
	MtlX Acos	mtlxacos	ND_acos	multiple
	MtlX Add	mtlxadd	ND_add	TexFloatOp / TexAColorOp
	MtlX Array Append	mtlxarrayappend	ND_arrayappend
	MtlX Asin	mtlxasin	ND_asin_float	multiple
	MtlX Atan2	mtlxatan2	ND_atan2_float	multiple
	MtlX Ceil	mtlxceil	ND_ceil_float	multiple
	MtlX Clamp	mtlxclamp	ND_clamp	TexClamp
	MtlX Cos	mtlxcos	ND_cos	multiple
	MtlX Cross Product	mtlxcrossproduct	ND_crossproduct_vector3	TexVectorOp
	MtlX Determinant	mtlxdeterminant	ND_determinant
	MtlX Divide	mtlxdivide	ND_divide	multiple
	MtlX Dot Product	mtlxdotproduct	ND_dotproduct_vector3	TexVectorOp
	MtlX Exp	mtlxexp	ND_exp	multiple
	MtlX Floor	mtlxfloor	ND_floor	multiple
	MtlX Invert	mtlxinvert	ND_invert	TexFloatOp / TexAColorOp
	MtlX Invert Matrix	mtlxinvertmatrix
	MtlX Ln	mtlxln	ND_ln	multiple
	MtlX Magnitude	mtlxmagnitude	ND_magnitude	multiple
	MtlX Max	mtlxmax	ND_max	TexFloatOp / TexAColorOp
	MtlX Min	mtlxmin	ND_min	TexFloatOp / TexAColorOp
	MtlX Modulo	mtlxmodulo	ND_modulo
	MtlX Multiply	mtlxmultiply	ND_multiply	TexFloatOp / TexAColorOp
	MtlX Normalize	mtlxnormalize	ND_normalize	TexVectorProduct
	MtlX Normalmap	mtlxnormalmap	ND_normalmap
	MtlX Place2D	mtlxplace2d	ND_place2d_vector2
	MtlX Power	mtlxpower	ND_power
	MtlX Rotate2D	mtlxrotate2d	ND_rotate2d_vector2
	MtlX Rotate3D	mtlxrotate3d	ND_rotate3d_vector3
	MtlX Sign	mtlxsign	ND_sign	multiple
	MtlX Sin	mtlxsin	ND_sin	multiple
	MtlX Sqrt	mtlxsqrt	ND_sqrt	multiple
	MtlX Subtract	mtlxsubtract	ND_subtract
	MtlX Tan	mtlxtan	ND_tan	multiple
	MtlX Transform Matrix	mtlxtransformmatrix	ND_transformmatrix
	MtlX Transform Normal	mtlxtransformnormal	ND_transformnormal_vector3
	MtlX Transform Point	mtlxtransformpoint	ND_transformpoint_vector3
	MtlX Transform Vector	mtlxtransformvector	ND_transformvector_vector3
	MtlX Transpose	mtlxtranspose	ND_transpose

Pbr	MtlX Blackbody	mtlxblackbody	ND_blackbody

The following functions are supported in Solaris:

sin
cos

tan
sqrt

log
floor

exp
ceil

asin
acos

Reference

MaterialX website: https://materialx.org/
Doug Smythe (Industrial Light & Magic) and Jonathan Stone (Lucasfilm Advanced Development Group), MaterialX: An Open Standard for Network-Based CG Object Looks (Version 1.38), March 1, 2021: https://materialx.org/assets/MaterialX.v1.38.Spec.pdf
Niklas Harrysson (Autodesk), Doug Smythe (Industrial Light & Magic), Jonathan Stone (Lucasfilm Advanced Development Group), MaterialX Physically Based Shading Nodes (Version 1.38), February 2, 2021: https://materialx.org/assets/MaterialX.v1.38.PBRSpec.pdf
Doug Smythe (Industrial Light & Magic), Jonathan Stone (Lucasfilm Advanced Development Group), MaterialX: Supplemental Notes (Version 1.38) , February 2, 2021: https://materialx.org/assets/MaterialX.v1.38.Supplement.pdf
Solaris documentation: https://www.sidefx.com/docs/houdini/solaris/materialx.html

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