This tutorial shows you how to use V-Ray Decal on a curved object.
Overview
With V-Ray Decal you can easily project one material on top of another regardless of the target UV set. The object could be bumpy or flatter, curved or having straight sides. Moreover, you can also stack multiple V-Ray Decals that have different materials on top of each other. The projected materials can be masked based on textures.
In this tutorial, you will learn how to assign realistic stickers and labels particularly to a curved object. You will also see how to stack several stickers on top of each other. The scene used here contains a simple product setting with a single geometry - a bluetooth speaker. The material used for the speaker’s fabric parts comes from the Chaos Scans library.
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Workflow
Let’s first render the geometry without any V-Ray Decals on it, to see how it looks.
- Create a V-Ray Decal node inside a Geometry node in |obj| network.
UI path: |obj Network| > Geometry node > right-click > V-Ray > V-Ray Decal
- Place the decal onto the geometry where the decal image must be visible. Here, the image must be projected on the speaker’s central plastic part.
You can use the No Material Color option (V-Ray Decal parameters > Shading rollout) to set a specific color for the decal for easier placement. This is helpful especially when you stack several decals and want to adjust their positions.
- Inside the |mat| Network, create a Material for the decal. In this particular case, a simple V-Ray Material (VRayMtl) works fine.
- Then go back to V-Ray Decal parameters and set the VRayMtl as the V-Ray Decal material from the Shading rollout: V-Ray Decal > Shading > Material > Open floating bundle chooser.
- Load a Mask Texture in the Shading rollout. This texture is going to be projected onto the geometry. Note that this step is not mandatory; you can use the decal without a Mask Texture.
- Render.
The V-Ray Decal affects the fabric parts of the speaker, which is an unwanted result. You have two options: either exclude the fabric parts from the V-Ray Decal’s effect, or make the effect work only on the central plastics.
- Go to V-Ray Decal parameters, and select an Exclude Mode. Let’s set it to Exclude here, and then add Button, Fabric, and Metal to the Exclude list.
Now the V-Ray Decal’s effect is applied to the correct part of the speaker but the texture is cut at the top and bottom.
- If your mask texture is not projected properly too, try adjusting the Size parameter. Here, set the following values for the XYZ dimensions: X= 0.4, Y = 1, and Z = 0.5.
UI Path: V-Ray Decal parameters > Main rollout > Size
- Render again.
This time the mask texture fits within the decal bounding box. However, the sign looks too small and sits rather flat on the curved surface of the speaker. Let’s see how to bend it.
- Adjust the Bend angle. Here, a value of 50 for the Bend works well.
- Also turn the Enable the Fading by Normal Angle option on for a better result. This creates a fadeout gradient starting from the Normal Angle.
Keep the Normal Angle at its default value of 90.
- Render one last time.
- Render.
The decal material is projected over the geometry where it intersects it. The Mask is also affecting the projection. The text is bent along the curved plastic.
- Create a second V-Ray Decal, following the steps from the previous section. Position it properly and set its material and mask texture. Adjust all the decal parameters as you deem fit.
- Render.
The new V-Ray Decal is placed on top of the second V-Ray Decal and affects the logo letters. To fix this, let’s change the order of the decals and bring the first one on top.
- In the V-Ray Decal01 parameters, set the Z Order to 2.
- In the V-Ray Decal02 parameters, set the Z Order to 1.
- Render again.
Final Result
