Maya Texturing – Oded Maoz Erell's CG Log

Maya – Basic UV unwrapping

Posted on December 27, 2019December 28, 2019 by Oded Maoz Erell

Software:
Maya 2018

Steps for basic UV unwrapping:

Select all polygons.
Apply planar UV projection just to get rid of all the current UV seams.
Select the edges that that are intended to be UV seams.
In the UV Editor menu choose Cut/Sew > Cut.
Select all polygons.
In the UV Editor menu choose Modify > Unfold.
In the UV Editor menu choose Modify > Layout.
Scale and rotate the UV layout to fit the UV space.

Related:
Multiple UV layouts

Maya – Using Multiple UV Sets

Posted on December 27, 2019December 27, 2019 by Oded Maoz Erell

Software:
Maya 2018

Note:
This post isn’t about “tiled UVs” (“UDIM”), it’s about multiple UV sets (layouts).

Explanation:
Polygon mesh models can have multiple UV sets. this becomes useful when the UV layout that is optimal for a certain texture isn’t efficient for different texture (in the same material).
For example, we might have a model of furniture, or clothing, in which the UV layout that is best for the fabric weave pattern, isn’t the best for dirt and wear & tear, or stickers.
In such cases we can define different UV sets for the model, each suitable for a different texture.

In this example, having a separate UV Set for the logo texture allows placing it without affecting the checker texture that is displayed an all the surfaces:

To create multiple UV sets:

In the UV editor view, from the UV Sets menu, select UV Set Editor to open the UV Set Editor:
In the UV Set Editor, press the New button to create a new UV Set and double click it in the list to rename it:
Close the UV Sets Editor.
The UV Editor view now displays the new UV Set that is empty, and UV creation and editing operations will now affect the new UV Set.
To switch to edit a different UV Set, select it from the list at the bottom of the UV Sets menu:

To link a texture to a specific UV Set:

Make sure the texture is connected to the material set for the model.
Select the model.
Open Windows > Relationship Editors > UV Linking > Texture-Centric:
Select the wanted texture from the material texture list on the left and select the wanted UV Set from the models UV Sets list on the right:

Related:
Basic UV Unwrapping

More posts about Maya

Basic Cloth Material in Arnold for Maya

Posted on October 20, 2019October 21, 2019 by Oded Maoz Erell

Software:
Maya 2018 | Arnold 5

An example of a basic traditional (not scanned) cloth material setup in Arnold 5 for Maya using an aiStandardSurface shader.

The shading network uses a classic angle dependent color blend to simulate the color of the cloth being washed out at grazing angle of view.

Explanation of the node graph:

A black and white fabric weave texture that will serve as input for multiple shading channels.
* This is actually not the best example of such a pattern, and could be replaced with a much better texture.
A remapValue node is used to set contrast to the fabric pattern (reduce contrast in this case) prior to it being multiplied with the fabric colors.
* Note that only one of the textures RGB channels is connected to the remapValue node since it’s a float (mono) processor and not RGB.

* Note that depending on the fabric texture, you may have to design different curves to achieve the right effect.
Two colors are defined with colorConstant nodes:
A deep color as the main fabric color, and a washed out color for grazing angle view (“side color”).
An aiFacingRatio node is used as an input for incident angle info.
* Note that in this case I checked the node’s invert option to make it behave more like other systems I’m used to (if you don’t use invert, the angle blend curve in 5 will be different..)
A remapValue node used to set the angle blend curve or in other words, how much does the color appears washed out per change of view angle of the cloth surface.
* The longer it take the curve to become steep from left to right, the more the main color will be dominant before the washed out color will appear.
A colorCorrect node is used in this example just as a way to convert the remapped float value back to RGB for being multiplied with the cloth colors.
* We could also connect it directly to the individual float components of the RGB colors but this way the node graph is cleaner.
A multiplyDivide node is used to multiply the processed fabric texture with the 2 fabric colors “baking” the pattern into the color.
A blendColors node is used to blend the 2 processed fabric colors together according to the processed facingRatio angle input.
The result is the final cloth color that is connected to the aiStandardSurface shader.
An aiBump2d node is used to convert the fabric pattern to normal data that will be connected to the aiStandardSurface shader to produce bumps.
An aiStandartSurface shader serving as the main shading node for this material.
* Note that under Geometry the Thin Walled option is checked so that the Subsurface layer of the shader will act as a Paper Shader rather than SSS.
* The main cloth color is connected to the SubSurface Color input.

Getting Maya 3D Paint to work

Posted on December 28, 2018December 29, 2018 by Oded Maoz Erell

Software:
Maya 2018

Steps needed for Maya 3D Paint to work:

Set a project folder and save your scene.
* If your painting into an existing texture you can skip this step.
Make sure your model has UV coordinates.
Make sure your model has a basic Lambert material.
* If you’re using a different material/shader on your model,
Temporarily switch to Lambert just for the texture painting operation,
And connect the original shader with the painted texture map to the surface shader input of the shading group after you’re done painting.
In the Rendering tab toolbar, Double-Click the 3D Paint tool button to activate 3D Paint and also open its tool settings window.
Make sure the object is selected.
In the 3D Paint Settings window, go to the File Textures part,
Choose a material attribute to paint to.
* this would usually be Color because we are using Lambert temporarily anyway.
Click Assign/Edit Textures to open the Assign/Edit Textures dialog,
Choose a resolution and a file format for the new texture,
And than click Assign/Edit Textures button at the bottom of the Assign/Edit Textures dialog to create the new texture and close the dialog.
* If you already connected an existing texture file to the Lambert shader’s Color input you can skip this step.
Check Update on stroke and Save texture on stroke.
Set the viewport to Textured display mode.
Set paint brush settings.
Click the 3D Paint tool button to activate it and paint on the model surface.

Texture Color-Space in Maya

Posted on January 9, 2018January 9, 2018 by Oded Maoz Erell

Software:
Maya 2018

Along with the Filtering Type, and the File Path attributes,
The File Attributes for texture nodes in Maya have the option to set a Color-Space with which to interpret the color values stored in the file’s pixels.
For example, JPG and PNG files will be interpreted as sRGB Color-Space by default, which means the color values will be ‘linearized’ (their Gamma Correction will be removed), and EXR or HDR files will be automatically interpreted as ‘Raw’ (linear) Color Space.

When an sRGB file like a PNG is intended to serve as linear data, and not as image display. it’s sometimes needed to set its Colors Space attribute to Raw. this is usually the case with Bump maps and Normal maps.

Equivalent setting are also found in other 3D software, see Blender Texture Color Space.