HDRP Materials

Compared to URP, the HDRP materials have a ton of options. I showed a few of these options in the previous article, but in this article I want to dig in a little deeper since this is really what makes HDRP so awesome.

The HDRP was made to support projects that need high fidelity visuals. You can achieve photo realistic, physically based assets using these materials.

To begin, if you look at the inspector panel for one of the objects in the scene, and navigate to the material you’ll see this.

Daunting right? Well lets break it down into chunks. You’ll see this is sectioned off by Surface Options, Surface Inputs, Detail Inputs, Emission Inputs, and Advanced Options. So I’ll go over each thing.

SURFACE OPTIONS:

In Surface Options you have the ability to change how the surface of the material is rendered.

• Surface Type determines the Material’s surface. You can either choose Opauque of Transparent.
• Rendering Pass — When using the opaque surface type this has no effect. This is meant more for transparent. A Unity employee says “Rendering Pass on the Material are mainly use for transparent to say if you render in quarter resolutoin or before refraction, with opaque there is no effect.” In a forum I found.
• Cull Mode allows you to cull the front or back facing geometry.
• Alpha Clipping — “Alpha Clipping The Alpha Clipping option controls whether your Material acts as a Cutout Shader or not. Enable Alpha Clipping to create a transparent effect with hard edges between the opaque and transparent areas.” -Unity Docs
• Double-Sided and Double-Sided GI — Unity — Scripting API: Material.doubleSidedGI (unity3d.com)
• Material Type: This one is a doozy because there are lots of options, but lets go through em!

Standard Material Type: This applies the basic metallic shader workflow to the material.

Subsurface Scattering: This simulates the way light interacts with and penetrates translucent objects, such as skin or plant’s leaves. When light penetrates the surface of a material with this type, it scatters and blurs before exiting the surface at a different point.

Anisotropy: Say that 5 times fast… The highlights of anisotropic surfaces change in appearance as you view them from different angles.

Iridescence: This material type will appear to gradually change color depending on the angle of view. Really nice for things like bubbles and insect wings.

Specular Color : This is similar to the built in specular shader. Use this to create materials with a coloured specular highlight.

Translucent: Use this type and a thickness map tp simulate a translucent material. Translucent materials wont blur the light that transmits through the material unlike Subsurface Scattering types.

• Receive Decals: This determines whether a decal can be rendered on the surface of this material. I’ll get into decals later.
• Receive SSR: Does it receive Screen Space Reflections? I’ll get into this later as well.
• Geometric Specular AA: This allows you to perform Geometric Specular Anti Aliasing on this material.
• Displacement Mode: You have None, Vertex Displacement, or Pixel Displacement. I’ll dig into these in a later article.

After that we have:

SURFACE INPUTS:

With HDRP you’ll probably run into some options for ambient occlussion. I’ll dig into that soon. But you’ll see some sliders for ambience occlusion remapping, metallic remapping, and smoothness remapping. These are handy tools. Adjust these to your liking. You can get some really awesome results with the right settings.

Another thing unique to HDRP is the Mask Map.

Without getting into insane levels of detail, the mask map allows you to combine a metallic and a smoothness shader into one channel.

You’ll also see some of the usual stuff, normal map, base map, etc. These act the same as before. Bent normal maps, coat masks, are all unique to HDRP. I’ve never used either, so im not going to act like I know for sure what they are for, but with some googling Im sure its easy to find out!

DETAIL INPUTS:

This options gives us space for a detail map. Whats a detail map?

This allows you to overlay another set of textures on top on the textures in the surface inputs section.

Unity — Manual: Secondary Maps (Detail Maps) & Detail Mask (unity3d.com)

EMISSION INPUTS:

This is similar to the URP EMission section of the material. There is some extra customizability here though. You can adjust the exposure weight and decide whether you want to use the Emission intensity or use the emission intensity from the HDR color picker in luminance.

ADVANCED OPTIONS:

This is where you can decide whether to Enable GPU Instancing and change the Specular Occlusion Mode.

Enabling GPU Instancing: This is useful when a scene contains multiple copies of the same material. It uses an instance of the material in the scene resulting in fewer draw calls. This is good for things like grass and leaves. Things that are drawn several times in a scene. Super great for performance!

The Specular Occlusion Mode is good for reflection probes. This requires ambient occlusion and bent normal, so I wont dig into it now, but maybe later!

So in short, there are a LOT of extras in HDRP that can bring your scene from decent looking to as detailed as you want! In the following articles I’ll cover these options in a lot more detail as well as the global volume, and other volumes available. This article literally scratched the surface of the HDRP Standard Lit material.. there are a lot of others with their own sets of options. So I encourage you to research and make your scene look as awesome as possible!