3d:shading [mh8 Wiki]

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====== Shading / Textures =======


**PBR** (Physically Based Rendering) are best rendered with Cycles render engine. The material reacts to the environment and lighting in a physically realistic way. 

**HDRi** textures can be used on the World shader to bring lighting to the scene.

To turn off its display : **Render > Film** and tick **Transparent**.



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==== Texture Coordinates ====

For all the texture nodes use a **Texture coordinate** node (output //Object//) connected to a **Mapping** node (input //Vector//) in turn connected to the texture images (in/out //Vectors//) as illustrated below.

If you have **Node Wrangler** add-on activated, the keyboard shortcut **''CTRL + T''** will automatically generate these nodes.

{{3d:pbr-texture-coordinates.png?direct&800}}


Incidently, using **Node Wrangler** add-on you can select the **Principled BSDF** and use ''CTRL + SHIFT + T'' to open a bundle of maps and have them set-up as a Principled Texture.

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=== Base Color ===

Keep the diffuse image in ''sRGB'' colorspace but if your mapping on an object use a ''Box'' projection instead of ''Flat''.

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=== Roughness ===

For roughness use ''Non-Color'' colorspace and ''Box'' projection as well.


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=== Normal ===

For the normals use ''Non-Color'' colorspace and ''Box'' projection. Use a **Normal map** node to convert the output ''Color'' to the input ''Normal'' of the **Principled BSDF**

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=== Displacement ===

The displacement avoids the **Principled BSDF** and goes directly into the ''Displacement'' input of the **Material Output**. This is because the displacement actually affects the geometry of the object whereas the Principled BSDF affects the way it looks.

Displacement must be activated in the Options under the ''Surface'' tab (choose : Displacement and Bump instead of Bump Only)

Displacement works best when there are many polygons on the object (use of a **Subdivision Surface** modifier is advised) and adds a good bit of detail. The drawback is it takes a lot more processing power and it's use is not advised for games.

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<WRAP tip round>
__**Box Projection Method**__

Box projection has the **advatage** of being quick to setup, works with modifiers (e.g. bevel) and automatically updates if you modify the shape (e.g. extrude).

However, it **does not work** with a game engine, which require a proper UV Map (hence, we cannot choose the ''Object'' output of the **Texture Coordinate** Node).

__**UV Map Method**__

UV Map on the other hand requires to properly unwrap your object but once textured it can be exported easily to a game engine. The downside is you will see the seams, and there is no way to blend it so you should think carefully about where you place them, and keep your objects at a safe viewing distance. Another inconvenience is that you have to apply the modifiers for the seams to be set properly so it is slightly destructive.


Both these methods however keep the advantage of being able to easily change the PBR texture.

__** Texture painting **__

You can also load an image into a texture brush and paint directly on the object. In which case, choosing a random tiling and a large brush along with isolated-click painting instead of strokes can result in a good looking object. One drawback is the object has no roughness and the texture looks a bit flat.
</WRAP>

In the case of texture painting, there is a way to add a bit of normals and bumpiness using the data from the image texture and a few color ramps as so :

{{3d:bump-from-image.png?direct&500}}


==== Texture Atlas ====

A texture atlas is a custom image combining many different textures all in one image. 

It has the great advantage of asking the CPU/GPU to load only one image and objects are unwrapped to pick their textures from different pars of that image. 

The drawbacks are that you need equivalent maps for different values of roughness, metalness, normals and AO and each texture will have a lower pixel resolution (being part of a greater image)

This technique works very well to add a stunning level of detail to the shading of Low Poly environments instead of flat colors


| {{:3d:autumn-palette.png?direct&200|}} | Unwrap objects from side view with **Unwrap > Project from View** |
| ::: | Select all vertices and squash down along X axis |
| ::: | Place on desired color column |
| ::: | Scale along the Y axis and place according to desired result. |

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==== Texture Slots ====

Texture slots enable you to give different textures to different parts of a mesh. 

Select the parts of the mesh and select another slot material and click assign.

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==== Seamless textures ====

Seamless textures repeat themselves when scaled down without it being too noticeable at first glance. A pattern does become visible if you scale too much as the texture repeats itself.

There are two ways to scale : 



| {{3d:mapping-node.png?direct&200}} | {{3d:uv-edit-scale.png?direct&200}} |
| In the node editor, on the **mapping** node | In the UV editor, by scaling the unwrap. |

The second option is preferable when exporting the scene to a game engine as the UV unwrap (and it's scale) will be conserved in the export.



A handy feature of seamless textures is that they will continue applying if you modify your geometry. One good way to do this is with an edge slide (Shortcut : ''G'' + ''G''). If you want to edge slide beyond the existing geometry you need to remove clamping (Shortcut : ''C'' while edge-sliding).

{{3d:clamping-removed.png?200}}

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==== Procedural textures ====

Procedural textures are created by using nodes instead of images or photographs to create a material. Basic texture nodes are mixed together (often with a **MixRGB** node) and the Color output is then used to give both roughness and normals to the material.

{{3d:procedural-texture.png?800}}

When creating textures with this method it's important to think macro-details and micro-details and mix them together. The ''Scale'' value of the basic texture nodes can be used to this effect.

A rapid shortcut to create a mix node is to ''CTRL + SHIFT + RIGHT-CLICK & DRAG'' from one node to the other one that you want to mix.

The procedural textures can be very easily tweaked and modified. They do not require much artistic skills as opposed to the //creation// of textures based on images and photographs (although those are often available for free or a small fee on many platforms online). One downside however is that these textures need to be baked to be exported to a game engine, although that is a minor downside as baking is often required when exporting to game engines anyways.

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===== Sample Low Poly Shaders =====

==== Stone with noise ====

{{:3d:basic-stone-shader.png?direct&700|3d:basic-stone-shader.png}}

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==== Wood with noise ====

{{:3d:basic-wood-shader.png?direct&700}}

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==== Random colors from ramp ====

{{3d:random-material.png?direct&700}}

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===== Texture Painting =====

Texture painting can be done in the **Texture Painting** workspace.

To texture paint on an object, it needs to be UV unwrapped. (The default cube is already unwrapped).

You also need a texture image to paint on. To easily create one, in **Texture Paint** mode select the **Texture slots** drop down menu and click **''+''** to add a texture.

It will be automatically added to the material in the **Shader** editor.

==== Color picker & Color Palette ====

In the **Tool** tab, the **Color Picker** contains the color wheel to select different colors.

Hovering over a color in the 3D Viewport and pressing **''SHIFT'' + ''X''** will update the color picker to the color hovered over.

With a palette created and open, maintaining **''SHIFT'' + ''X''** and **''LEFT CLICKING''** will add the color to the palette.

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==== Masks ====

Masks can be added with the **Mask** brush but need a Stencil Mask to work on.

These can be found with the drop down menu next to the **Texture Slots**.

Once a mask is created and selected, simply paint with the **Mask** brush to apply a mask preventing further painting on that area with another brush.

Remember to tick the **Fake user** icon to save the mask in the project file.

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==== Texture images ====

Texture images can be added in the **Texture** menu of the **Color Picker**

You can duplicate a brush to create a texture image on the cloned brush.

Once a texture image is created in the **Color Palette** use the **Texture** tab to open an existing image.

Back in the **Color Picker** (**Tool** tab), under the **Stroke** property switch the **Method** to **Anchored**

{{:3d:texture-paint-image-texture.png?direct&200}}

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===== Decals using UVs =====

==== Result ====

{{:3d:decal-with-uv.png?direct&700|}}

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==== Walkthrough ====

This works for objects that are already UV unwrapped.

In the shader editor, add an image texture to the base color.

Using **Node Wrangler** use **''CTRL'' + ''T''** to auto add the mapping branch.

Replace the **Texture Coordinate** node by a **UV map** node.

If necessary change the scale of the bottom texture.

Duplicate the entire branch (with the Principled BSDF) and in this second branch replace the image with background alpha 0 channel to use as decal.

Use **''CTRL'' + ''SHIFT'' + ''RIGHT CLICK'' & ''DRAG''** to mix the two Principled BSDF togethers.

Use the Alpha of the decal image as factor for the mix. Use **''ALT'' + ''S''** on the mix to swap the channels if necessary. **The decal should be on the bottom input**.

With the object selected, in the **Data** property panel, under UV Maps, add a second UV Map. Rename it decal and use it as the UV Map for the Vector coordinates of the mapping on the decal texture.

Select the object and smart UV project it. Select all, scale it down and put it in an alpha 0 portion on the decal image.

Select the faces where you want to decal and either **project from view** or **angle based projection** and scale/rotate to get the decal into position.

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===== Eevee Bloom =====

Open the **Compositing** workspace.

Tick the **Use Nodes** option.

Add a **Viewer** node and render the scene. Connect the render to the **Viewer** node.

Optionally add a **Image Editor** viewport and view the **Viewer node** for a clearer view of post-process.

Use **''SHIFT'' + ''RIGHT CLICK''** over the noodle to insert a **Reroute** and after the **Render Layers** node add a **Glare** node.

Switch to **Fog Glow** and adjust settings.

{{:3d:eevee-bloom.png?direct&500|}}

When in Layout view, Rendered preview, the Viewport Shading dropdown menu enables to activate the Compositor when in Camera view, Always or never (default).

This is useful to get any post-process effect to display in real-time in the Layout view.
===== Resource sites =====

Great places to look for textures : 

  * **[[https://polyhaven.com/|PolyHaven]]**

  * **[[https://freepbr.com|Free PBR]]**