This tutorial covers how to make paper objects with VRayMtl2Sided.
Overview
Paper allows light to pass through it even though the actual substance it is made of is not really transparent or refractive. The light passing through the paper is described as translucency. When the paper is illuminated from the back side we can see characteristics of the opposite side at the front.
VRayMtl2Sided is the best choice for representing paper and other translucent objects.
In this tutorial, we examine how to use VRayMtl2Sided to create a realistic paper material. The geometry we use is a paper lantern which has no thickness and its sides are made of 4 planes.
Step 1: Create the front material
Let's create the Front material of our paper lantern. Open the Hypershade and go to Create panel > VRay section > VRayMtl.
Then link a File texture to the Diffuse Color slot of the Front material.
Set the parameters of the Front material.
– set the Reflection Color to gray to introduce some reflectivity.
– reduce the Reflection Glossiness to around 0.75 to blur the reflections.
– keep the rest of the parameters at their default values.
Different types of paper or other translucent objects may require different settings for VRayMtl2Sided and the front and back sub-materials. For example, to make a magazine cover, the paper material needs to be glossier and more reflective than the one for the lantern.
Here's how the front material looks on its own when rendered.
Step 2: Create the back material
Let's create the Back material.
Just like in Step 1, we need a VRayMtl but with a different diffuse texture.
We can also use a Bump map texture to introduce some creases and crumpling to the paper.
Here's a render of just the Back material on its own.
Step 3: Create a V-Ray 2-Sided material
VRayMtl2Sided has Front and Back materials that are applied to the shaded surface according to its polygon normals. If no Back material is used, then the Front one is applied on both sides.
Link the Front and Back materials that were created in the previous steps to their respective slots in VRayMtl2Sided.
Step 4: Adjust the translucency
Translucency determines which side (front or back) relative to the camera is more visible in the render.
Select the VRayMtl2Sided node. In the Parameters rollout, set the Translucency color to the desired value. Note that darker colors make the VRayMtl2Sided look more solid, while lighter colors make it more sheer and allow more light from the back side to pass through the object.
Change the slider below the image to the right, to see a few different examples of the Translucency value in the 2-Sided material.
Translucency is set to black. No light is passing through and the back material is not visible.
Translucency is mid-gray, allowing light from the back to pass through, making both materials visible.
Translucency is set to white, allowing all the light to pass through. Only the back material is visible.
Step 5: Final image
For the final image, the scene is slightly tweaked for a more artistic look:
- the Rect light that's illuminating from the side is made blue-ish and colder;
- the Sphere light inside the lantern is made yellow-ish and warmer and its intensity is increased.
