We are going to make a simple grid and apply a texture map to it. This technique is commonly used for making low-polygon, flat objects when depth is not visually important. Examples of this include: chain link fences, ferns, leaves, and paper money. This technique can also be used with trees, plants, grasses, or other objects that are seen in the distance. This techniques has also been used on architectural mock-ups for the placement of people images.
To complete this tutorial you will need to download the following files:
Ideally, you would follow the directions below and set-up your own shader so you will learn the process for later tutorials. However, I have supplied some pre-made shaders in Carrara's .cbr file format for your use if you wanted to skip the construction of the shader and deal only with the UV portion of this tutorial. These .cbr files are listed after Step 2.Create a simple grid in the the vertex modeler by going to Construct -> Insert 3D -> Grid. A pop-up dialog box will appear asking you for what settings. Change the U Vertex Count to be 5 and leave the other options as is. The resulting grid can be seen in Figure 1.
Figure 1.
With the model constructed, we will create the shader for the leaf object. Enter the texture room and apply the texture maps to the following channels:
*The alpha channel is available in C4+. For C3, please download the below .cbr file and review how I used the Alpha map to trim the texture and make it see-through.
These channels in your shader should look like Figure 2.
Figure 2.
Return to the Vertex Modeler and Click on the UV Map tab (this tab is called UV Mapping in C3) in the properties panel. Then click on the UV Editor button. These can be seen in Figure 3.
Figure 3.
The UV Editor window will appear as seen in Figure 4. Take a few moments to familiarize yourself with the different tabs, checkboxes and menu boxes, but do not change any values at this time.
Figure 4.
Click on the Projection Tab. Then select the "planar" type from the drop-down menu. Click on Apply. You will notice that the UV's lines above the leaf image changes to match the project type that you selected. This is seen in Figure 5.
Figure 5.
Next to the image of the leaf on the right side is a set of icons. These tools will allow you to adjust the UV's to fill the full size of the image. Select the scale tool. Slowly and carefully, click and drag the UV's while the vertexes are highlighted in red. You will notice that the scaling on the right edge will go pass the right border and re-appear on the left side. This is normal and is a characteristic of the UV Editor that you should take special notice in. After you scale the UV's, you should select the translate tool (the round button has the shaped of an arrow) and move the UV's to fix the image properly. You can refer to the preview display to ensure that the placement is accurate. Your UV's should look like Figure 6.
Figure 6.
Click on the OK button on the bottom of the UV Editor.
Your leaf object should now be set with the proper UV's. You can go back to the Vertex Modeler or Assembly Room and perform a spot render or go into the Render Room and render out this scene. NOTE: If you do not change the light through transparency option in the render room, the leaf will appear to have a white fill around the texture to the edge of the grid. You can render an image like the one in Figure 7 (I did a test render from the Vertex Modeler).
Figure 7.
This concludes the first in the UV series. You should have learned how to set up a very simple shader, create a grid object in the vertex modeler and how to apply a planar projection type from the UV Editor. You can further your own studies by playing with the UV unwrapped model in the Vertex Modeler. Try curling the edges and creating a bowl-shaped appearance. This will cause the texture to stretch and give you an idea how UV mapping affects a model when it is animated or otherwise deformed.
If you would like to compare your results with mine, I have supplied finished tutorial results in several Carrara formats below:
Here is a sample of what you can do by deforming the grid and by doing some extra shader steps. (I lowered the bump amplitude before render this image, so the vains are not as harsh.)
