SkIndigo Texture Mapping Tutorial
This tutorial is for SkIndigo versions 2.0.X. However, it may also work for future versions.
For the purpose of this tutorial, a 'SketchUp' material refers to the material and attributes that can be edited using the SketchUp Materials Window (Paint Bucket). An Indigo material refers to a material that has been modified using SkIndigo material editor. In this tutorial, a 'texture' means an image file such as a JPEG or Bitmap image.
There are three cases (listed in order of simplicity) that you will encounter when you are adding texture maps (bump, clip, exponent, etc.) in SkIndigo.
1) There is a texture applied to the SketchUp material and you want to use the same texture for another map channel (i.e. bump, clip, etc.)
2) There is a texture applied to the SketchUp material and you want to use a different texture for another map channel.
3) There is no texture applied to the SketchUp material and you want to assign a texture to a map channel.
This tutorial will discuss how to apply textures for these three cases. This tutorial requires the following files:SkIndigo Textures Tutorial.skp, brick_displace.jpg
Case 1 - Using the same map for Albedo and Bump Map
1. Using the SketchUp Paint Bucket, paint the 'Tile' material on the three sides of the box and the bottom.
Case 1 - Using the same map for Albedo and Bump Map
1. Open the 'Tile' material in the SkIndigo material editor.
2. Note that the Albedo map is set to 'SketchUp' by default.
There are four choices in the 'Map' drop-down list. You can choose 'None', 'SketchUp', 'External' or 'Shader'. When you choose 'SketchUp', this means that the texture that is applied to the SketchUp material (i.e. Tile_Ceramic_Natural.jpg) will be used for that particular attribute. For example, if you change the Displacement Map drop-down list to 'SketchUp' the texture Tile_Ceramic_Natural.jpg will be used for the displacement map as well.
If there is no texture currently applied to the SketchUp material and you have selected, 'SketchUp' from the map drop-down list, then NO texture map will be used for that particular attribute. This is equivalent to selecting 'None' from the drop-down list.
Case 1 - Using the same map for Albedo and Bump Map
1. Change the Bump map drop-down list to 'SketchUp' and set the value to 0.02. This will set the bump map to the same texture that is applied to this SketchUp material (Tile_Ceramic_Natural.jpg)
Case 1 - Using the same map for Albedo and Bump Map
1. If you click on the '..' button, the SkIndigo Texture Editor will open.
2. Notice that the UV set for the bump map is set to 'SU' by default. This means that the texture position (UV coordinates) for the bump map will be the SAME as the position of the texture that is currently applied to the SketchUp material. Therefore, the bump map and the albedo map will be the same texture and be at the same position.
3. Click the 'Accept' button and render the scene.
Case 1 - Using the same map for Albedo and Bump Map
The render.
Next....Case 2
Case 2 - Using a different map for the Albedo and Displacement Map
Now we will create a material that uses different maps for the albedo and displacement maps.
1. Open the Paint Bucket and paint the 'Brick' material on the three walls.
Case 2 - Using a different map for the Albedo and Displacement Map
1. Open the 'Brick' material in the SkIndigo material editor. No changes are required to the Albedo map because we want to use the SketchUp texture (brick.jpg) for the albedo map.
2. Select 'External' from the displacement map drop-down list. This tells SkIndigo that you will be using an External file for the texture map.
3. Change the displacement value to 0.015. Remember that Indigo base units are meters so this value would result in a displacement of about 1.5cm for the pure-white areas of the displacement map.
4. Click the '..' button to open the SkIndigo Texture Editor.
Case 2 - Using a different map for the Albedo and Displacement Map
1. Click the 'New...' button to load a new texture map.
2. Find the brick_displace.jpg file that was included with this tutorial and select it.
3. Click the 'Open' button.
4. Click the 'Accept' button in the Texture Editor.
Notice that there is no need to modify the UV Set. It is set to SU (SketchUp) by default which means that the displacement map will be positioned the same as the SketchUp texture that is applied to this material (i.e. brick.jpg)
Case 2 - Using a different map for the Albedo and Displacement Map
Before rendering, set the Max Subdivisions value for the 'Brick' material to 8 and set the Pixel Threshold value to 1.0. Increasing the number of subdivisions and decreasing the subdivision pixel threshold value will result in a finer (higher-resolution) displacement. These are desirable settings for a high-contrast displacement map such as brick. For comparison, try lowering the max subdivisions setting to 4 and rendering to see the effect.
Case 2 - Using a different map for the Albedo and Displacement Map
The render.
Next....Case 3
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
Now we will create a material that uses a displacement map but does not have a texture applied to the SketchUp material. We will do this by modifying the 'Brick' material.
First, uncheck the 'Use Texture Image' option using the SketchUp materials window.
There is no need to modify the albedo map drop-down list. We can leave it as SketchUp. Since there is no SketchUp texture applied, there will be no albedo texture and the plain brownish material color will be used instead.
If you try to render the scene now, the displacement map will be positioned using the SketchUp default UVs. This may not be what you want. In order to have control over the texture position, you have to use SkIndigo UV mapping.
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
1. First, select the faces that you want to position the texture on.
2. Click on the '..' button for the 'Brick' material displacement map
3. Select a custom UV set from the drop-down list (1,2, or 3). For this tutorial, select '1'.
4. Click the 'Position Map' button.
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
When you click the 'Position Map' button, a special material will be added to your SketchUp materials called 'SkIndigo UV Helper'. This material is intended to only be used for positioning texture maps. All of the faces that you had selected will be changed to this special material so that you can start modifying the texture position.
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
Change the size of the texture by changing the size values in the SketchUp Materials window. Alternatively, you could right-click on an individual face and use the SketchUp texture positioning tools.
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
1. Make sure that the three wall faces are still selected. If not, re-select them.
2. Right click on one of the faces and select 'SkIndigo UV Mapping->Save UVs to set 1
Recall that UV set 1 was the set that you chose from the SkIndigo Texture Editor. This operation will store save the current texture position OF THE SELECTED FACES to UV set number 1. You can save up to three custom UV sets using this method.
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
The UVs have now been saved for the three selected faces.
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
Before rendering, make sure you paint the 'Brick' material back onto the wall faces.
Case 3 - Using a displacement map without a texture applied to the SketchUp material.
The finished render.