This tutorial guides you through the process of creating desert sand using multiple V-Ray Decals.
Overview
This article shows you how to stack multiple V-Ray Decals to create the shading for rocks, terrain and other objects for a realistic desert appearance. The decals are a useful way to project shaders onto objects and don't need UVs to work.
Here, you will discover how to arrange the decals in the desired order, limit their impact to specific objects, and control the bump effects and spread on the affected surfaces.
The tutorial scene includes a deformed terrain and a selection of Chaos Cosmos rock and foliage assets in the foreground, creating a captivating sand-dunes landscape.
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Workflow
First, let’s render the start scene without VRayDecals to see how it looks. A default gray VRayMtl is applied on the terrain.
For more precise control, use separate decals with different settings for the foreground and background geometries. Assign the same sand material to all the decals and adjust the decals settings to achieve different looks for the foreground and background. The background can have a simpler appearance with fewer details, while the foreground can be more complex with intricate details for close-up views that can be achieved through displacement.
In Step 1, separate VRayMtl materials with different diffuse colors are used to facilitate the placement and scaling of the decals. Once the decals are set, a single sand material will be assigned to all of them.
In this example, the default working units are kept in centimeters. To change them, go to Windows > Settings/Preferences > Preferences > Settings > Working Units.
Step 1: Create VRayDecals
- Create the first VRayDecal (VRayDecal1) and set its dimensions to:
Width = 55000
Length = 80000
Projection Depth = 7000
- Adjust the decal’s position to cover all foreground and midground terrain geometries, as shown in the image. Also make sure the Height position is adjusted so that the scene objects are fully covered.
- Create a VRayMtl and apply it to VRayDecal1. For better visibility during scene setup, change the Diffuse color to a different color, such as blue.
- Render the scene to see the result.
In this tutorial, three decals are used for educational purposes. In a real case scenario, it’s possible to omit the first decal and apply a simple sand material directly to the background sand dunes. However, if you have objects in the background that only need to be partially covered by the material, you can make use of the decal and its Normal angle and Fade out angle options. For more information on this technique, you can refer to the V-Ray for 3ds Max How to Create Snow with VRayDecal tutorial.
Front
Perspective
Top
Move the slider to see the other images.
Here's the rendered decal that covers all the scene objects. However, you need to remove its effect from the stones, palm trees, and the lake.
- Open the Exclude List in the VRayDecal1 parameters and add the following objects and sets of objects:
Water
Terrain_01_A
Terrain_01_B
Terrain_01_C
Stones_Foreground
Foliage_Foreground
These objects are now excluded from the VRayDecal1 projection, and the decal only affects the background objects and the foreground palm leaves. Later, you will add a simpler sand material without displacement to the decal.
Now the decal covers the entire background terrain while excluding the lake, rocks, and trees. For the trees and rocks, you are going to utilize separate decals to achieve the desired effect.
- Let’s proceed to create another VRayDecal, called VRayDecal2, specifically for the foreground sand. Set the following dimensions to it:
Width = 14000
Length = 22000
Projection Depth = 1500
- Adjust it so it covers all objects in the foreground and the background stones and foliage, as shown in the image.
- Create a new VRayMtl with a green Diffuse color and apply it to the VRayDecal2.
- Add the following objects and sets to the VRayDecal2 Exclude List:
Water object
Palm_Leaf_A
Palm_Leaf_B
Stones_Foreground
Foliage_Foreground
Thus, the decal affects only the foreground terrain.
- Render the scene.
Front
Perspective
Top
Move the slider to see the other images.
Here’s the rendered decal. It affects only the foreground sand, while leaving the rocks and trees unaffected.
- Let’s add the last VRayDecal, called VRayDecal3, to the closeup stones and immediate sand. The dimensions of this decal are as follows:
Width = 1500
Length = 2500
Projection Depth = 1500
- Adjust the decal position as shown in the image.
- Exclude the following objects from the VRayDecal3 Exclude List:
Water object
Palm_Leaf_A
Palm_Leaf_B
Foliage_Foreground
Now the decal affects only the Foreground_Stones set.
- Add a new VRayMtl with a yellow Diffuse color.
- Render the scene to see the result.
Front
Perspective
Top
Move the slider to see the other images.
In the rendered image, it’s apparent that the third decal (VRayDecal3) is positioned higher than the second decal (VRayDecal2) so it overlaps it and projects the applied material on top of VRayDecal2. VRayDecal3 is visible on the terrain.
To achieve a more precise projection of VRayDecal3 (i.e. force it only over the foreground rocks) as well as have individual control of the terrain decal, you have a few options. Either move the VRayDecal3 along the Y axis, placing it below the VRayDecal2; or just exclude the terrain object from the VRayDecal3 Exclude List. A third option is to adjust the ordering of the decals. This streamlines the process and spares you the trouble of making extensive position adjustments or object exclusions.
- In the Parameters rollouts of VRayDecal1 and VRayDecal2, set the Order to 2.
- Set the Order of VRayDecal3 to 1.
The Decals are set and you can proceed with the creation of the sand material.
Step 2: Create Materials
Let’s use a premade sand material from the Chaos Cosmos Library.
- Open the Chaos Cosmos Browser from the V-Ray toolbar. Locate and download the Sand A01 200cm material. Import the downloaded material into the scene.
- In the Hypershade, locate the place2dTexture node associated with the imported sand material. Set the Repeat UV values to 100 by 100. This tiles the sand texture and decreases the scale of the sand.
- Set the Sheen Color to a light brown color, such as rgb (0.54, 0.45, 0.37).
- Set the sheen Amount to 0.8 and the Sheen Glossiness to 0.6. This creates a falloff-like effect on the sand dunes and makes them more pleasant.
- Render the scene to see the updated result with the applied sand material.
The material looks rather flat. Let’s add more details on the front with the help of V-Ray Displacement.
Step 3: Add Decal Displacement
- Select VRayDecal2 and navigate to its parameters.
- In the Displacement rollout, click the Displacement Texture map slot and create a File texture node.
- Load the premade Sand_Displacement_Rough texture from the assets folder. The texture represents a desert-like sand relief with a noisy overlay to bring up some bumps as detail.
- Set the Repeat UV of the texture (in the place3dTexture node) to 38 by 20.
- Back in the VRayDecal2’s Displacement rollout, set the Displacement Amount to 8 and the Displacement Shift to -2.
- Render the scene.
Here’s how the sand turned out.
Let’s try with a smoother version of the sand - load the Sand_Displacement_Smooth texture and render the scene.
In the previous image, the sand looks more like beach sand, while the current render resembles much more a finer desert sand.
Step 4: Set VRayDecal Angles
Let's explore how the Normal Angle and the Fade Out Angle options of the VRayDecal can improve the sand material projection. Focus on the foreground stones.
- Select VRayDecal3 and navigate to its parameters.
- Set the Normal Angle to 15 and render the scene.
The sand material is now projected in a subtler and more natural way, with the exception of the sharp border where it meets the stone material. To achieve a smoother transition, use the Fade Angle option.
- Enable the Fade Out angle and render.
It seems that the Fade Out Angle value needs to be lowered a bit to reintroduce more of the stone material and enhance the fine displacement detail.
- Set the Fade Out Angle value to 40 and render.
Step 5: Set VRayDecal Bumps
Now let’s explore the decal’s bump option, which provides you with the flexibility to use the bump of the applied material or blend it harmoniously with the bumps of the underlying object’s material.
- Select the VRayDecal3 and disable the Use Only Decal Bump option.
- If you keep the Surface Bump Amount to its default value of 1, the surface bump (the bump of the underlying object) is fully visible. By decreasing this value, you can blend the bump maps of the decal material and the stone object material. Let’s set the Surface Bump Amount value to 0.7 and proceed to render the scene.
Final Image
The rendered decal looks flawless, resulting in a composition that is not only more realistic but also visually captivating.