Introduction


  • This presentation will take you through adding texture detail to a model using various V-Ray textures to add dirt and patina, as well as render as a wireframe
  • The information centers around the VRayEdgesTex, VRayDirtTex and VRayCurvatureTex texture nodes
  • This lesson topic is approximately 40 minutes in length
  • Presentation covers all 3 Learning Cycles for the Lesson Topic – Lecture, Demonstration, and Activity

 


 


Contents


Overview
Available Materials
Lecture
Demonstration
Activity                                 
Additional resources                                                                                


Overview


Goal – Create more interesting shading networks by incorporating custom V-Ray Textures into our materials
Objective – We will incorporate three of the V-Ray Textures into our 3D scene           

Outcome – You will learn a few different ways to apply the VRayEdgesTex, VRayDirtTex, and VRayCurvatureTex nodes to your materials to achieve specific effects

 


 

Available materials


To set up the lesson follow the links below and download all available materials.

Lesson plan download
Presentation (Lecture) download
Demonstration tutorial download
Scenes & Assets download                                                                                                                                                            


Lecture



1. Terminology

Custom textures help you achieve special render needs and effects

Here’s some terms to know when thinking about V-Ray textures:

  • Self Occlusion
    • Occlusion darkens areas of an object based on details in the geometry, like creases and folds
    • Anywhere where the angle from one face to another face is less than 180°, there may be occlusion
  • Invert Normal
    • Face angles above 180° can also create this darkening effect
  • Sampler Info
    • A node that provides detailed information gathered about any point on a surface which can be used to calculate advanced rendering techniques

 

 a) Edges Texture Overview

  • Allows you to render out the wireframe of a mesh
    • Edge Color – the color value of the polygonal edges
    • Background Color – the color value of the faces between the edges
    • Show Subtriangles – used with subdivision and displacement to show the edges of the generated sub-triangles
  • When applying the VRayEdgesTex to geometry with displacement mapping, the original faces and edges of the mesh before the surface is tessellated and displaced are seen in the render of the Edges texture

 

 

b) Edges Texture Parameters

  • Show Hidden Edges – internal face edges will be visible (triangles instead of quads)
  • Shows Triangles over Quads

 

 

Show Hidden Edges: Off

Show Hidden Edges: On

 

 

  • Size can be adjusted using the Width Type and setting the value in either World units or Pixels

 

 

Width Type: Pixels at 1.0

Width Type: World units at 0.1

 


c) Dirt Texture Overview

  • Used to simulate a variety of effects, like dirt in crevices, to produce an ambient occlusion pass
    • Occluded color – the color that will be returned by the texture for areas that are occluded or covered by geometry
    • Unoccluded color – the color that will be returned by the texture for areas not covered
  • NOTE: Both the Occluded and Unoccluded color parameters can use a texture map, not just a color value
    • Radius – the amount of area (in scene units) where the VRayDirt effect is produced
  • Can also use a texture to control the value
    • Falloff – controls the speed of the transition between occluded and unoccluded areas to smooth the occlusion effect

 

 

d) Dirt Texture Parameters

  • Distribution – forces the rays to gather closer to the surface normal
    • Higher Distribution value narrows the occlusion effect closer to the contact edges; it makes the darer areas tighter, less broad
    • For ambient occlusion, set this parameter to 1.0 to get distribution similar to the ambient lighting on a diffuse surface

  

 

Distribution: 0

Distribution: 1

 

 

  • Invert Normal – will change the direction of tracing the rays
    • When it is Off the rays are being traced outside the surface, when On they are traced inside the surface
    • Allows us to revert the effect with respect to surface normals - e.g. instead of crevices, open corners will be shaded with the occluded color
    • This is usually not desired in most renders, but can be useful for some looks

 

 

Invert Normal: Off

Invert Normal: On

 

 

  • Ignore Self Occlusion – the object with dirt texture applied to it will not occlude itself
    • It will still be occluded by other objects in the scene
    • Use this option when you want to accentuate contact shadows

 

 

Ignore Self Occulsion: Off

Ignore Self Occulsion: On

 


e) Curvature Texture Overview

  • Samples the underlying mesh for its curvature
  • Allows you to add detail in crevices much like V-Ray Dirt does, however instead of adding “dirt” or darkening to areas that are occluded by geometry, the Curvature texture darkens areas that have curvature to better define cracks, ruts, fissures, etc.
    • A region around each shaded point is sampled with additional rays (similar to VRayDirt) and all additional normals are averaged to get a "smooth" normal at the original point
    • The color at each shaded point is a greyscale value: darker values are dents (or holes), lighter values are peaks in the surface curvature
    • The parameters should be adjusted by trial and error since they generally depend on the scale used; the defaults might not be appropriate at all in some cases.

 

 


 

Dirt Texture

Curvature Texture

 

 

Curvature is a good way to blend between materials (like red and blue here) to give a worn out look particularly at crevices, seams, and at the edges of rounded corners

f) Curvature Texture Parameters

  • Subdivs – controls the number of samples around each shaded point
  • Sample spread – controls the radius of the sampled region
  • Min/Max Output Color – an option map the output color to a range that is different than 0-1
    • Makes the output texture darker or lighter
  • Scale – adjust the scale relative to which the curvature is measured

 

 

Conclusion


a) Self Occlusion

  • When the ambient occlusion effect is seen inside an object’s own detail

b) Invert Normal

  • Flips the occlusion effect from face angles less than 180° to greater than

c) Sampler Info

  • Sampled information from points on a surface to help create advanced shading networks

 

                                                                                                                


Demonstration



Time to see it work!

Watch while I demonstrate how to create and configure the V-Ray textures to build an interested in look for our robot.
Demonstration tutorial

 

                           

 


Activity



Time to do it yourself!

Use the provided  scene file to recreate the cinematic look as you have seen me demonstrate.
We have also provided a final scene for your reference.

 

 

Dialing in the right values

  • Layered Texturewith remapHsv connected to bump Map of vrayBumpMtl (Value points 0,0; 0.137,0.033; 0.191,1 w/ Spline int.)
    • dirtMask_W_02.jpg Multiplied over vrayCurvature texture
    • vrayCurvature with Sample spread = 0.600
  • VRayMtl with vrayDirt texture connected to Diffuse Color used as Base Material for vrayBlendMtl
    • Occluded Color =
    • Unoccluded Color =
    • Radius = 2
    • Distribution = 4
    • Bias Y = 2
    • Ignore Self Occlusion = On
  • Blue chrome vrayMtl created for Coat 0 in blendMtl
    • Same HSV remap from Bump used for Blend Amount
  • Gray/Green dust vrayMtl created for Coat 1 in blendMtl
    • Snow texture used for Blend Amount
  • VRayBlendMtl used as Base Material for VRayBumpMtl

 

                        


Additional resources


Find more training resources listed below: