20.10.20265 min

PBR Materials in Corona: Map Setup in 3ds Max

In Corona Physical Material, connect Base Color to the base color, Metalness to metalness, Roughness to roughness and Normal through CoronaNormal to Base bump. This door-hardware example explains the wiring and common import mistakes. Corona Legacy Material has different inputs, so transferring the connections requires a check.

Prepare maps for the material workflow

The metal door detail in the lesson already has UVs and textures exported from Substance Painter. The Physical setup uses Base Color, Metallic, Roughness and Normal. These maps describe different properties of one surface and must match the same UV layout.

When exporting from Substance Painter, inspect Output Template and Output Maps. If the preset does not produce Base Color or Metallic, add the required outputs: a color output for Base Color and a grayscale output for Metallic. Save the template with a clear name for subsequent exports.

Extra Diffuse and IOR maps are used in the Legacy comparison. Do not substitute them for the Physical maps merely because they are in the same folder. Identify the intended workflow for each material first.

Create Corona Physical Material and connect color

Open Slate Material Editor with M, add Corona Physical Material and assign it to the required part. The lesson isolates the hardware through Multi/Sub-Object; make sure you replace the correct material rather than the finish of the whole door.

Load Base Color using Bitmap and connect it to Base color. It supplies the surface color and also influences the reflection tint on metallic regions. Inspect this stage in interactive rendering before adding the remaining properties.

Changing color alone does not create a metal. Next, the Metalness map determines which surface regions are metallic and which are non-metallic.

Separate color maps from control data

Base Color is usually exported as an sRGB color texture. Metalness, Roughness and Normal contain control data and need to be read without the color transformation used for an ordinary color image.

In the demonstrated Bitmap interface, maps labeled Raw are imported with Override Gamma 1.0. This is specific to the lesson's workflow. In a newer interface with different color management, check the corresponding data interpretation rather than copying the field name blindly.

Connect Metallic to Metalness and Roughness to Base rough. Light Metalness regions represent metal; dark regions represent non-metallic areas. Name the nodes by their function to avoid feeding a color image into a control input.

Color-map and Metalness wiring in Slate Material Editor — Base Color and Metallic feed the Physical material's Base color and Metalness inputs. 00:06:59

Route Normal through CoronaNormal

Connect the colored normal map to the CoronaNormal Normal input. Connect its output to the Physical material's Base bump. This interprets the image as surface-normal directions.

Inspect the relief in interactive rendering. If bumps look like dents, identify the exported map convention and check Flip green (Y) in the CoronaNormal documentation. There is no universal switch combination for every normal map.

Do not enable Swap red and green as a mandatory fix for every OpenGL map: it performs a different operation. Account for gamma handling as well; Add gamma depends on how the image has already been loaded.

Normal-map Bitmap and the intermediate CoronaNormal node — The normal image feeds CoronaNormal before being connected to the material. 00:08:00

Handle Roughness and Glossiness correctly in Legacy

Corona Physical Material accepts Roughness directly. The demonstrated Legacy material uses Refl. gloss. for the corresponding input. Roughness needs inversion in that setup; the lesson places Color Correction with Invert between the map and material.

Inspect the highlights again after changing the connection. Roughness and glossiness describe opposite directions of change, so wiring them identically changes the surface appearance.

Metal behavior is also assembled differently in Legacy: reflection and Diffuse are adjusted separately in the lesson. For a new material, start with Physical and Metalness; use the older setup when interpreting an existing scene.

Color Correction with Invert and Corona Legacy Material — For Legacy, the roughness image is inverted using Color Correction. 00:13:59

Validate the base material before decorative adjustments

Once the main maps work, artistic adjustments can follow. The lesson combines CoronaAO with the color map for dirt, but the effect needs inspection on the actual part. Get the base material right first instead of hiding errors behind extra darkening.

Compare the material under unchanged lighting and camera position. Modify one connection at a time to identify whether an issue affects color, reflection or small relief. Inspect the hardware together with the door; an isolated preview sphere does not show the full context.

Confirm the material is assigned to the intended part.
Check the color handling of each map.
Check Metalness and the chosen material's roughness input.
Make sure Normal passes through CoronaNormal.
Inspect relief direction and highlights in the scene.

Questions and answers

Why does the metal part look like plastic?

Check Metalness and material assignment. A color map alone is insufficient; in Physical, Metallic must feed Metalness and be interpreted as control data.

Can Roughness connect directly to Refl. gloss.?

For the demonstrated Legacy setup, invert Roughness through Color Correction first. In Physical, use Base rough without that inversion.

Why does the normal map produce incorrect relief?

Check CoronaNormal, color interpretation and map convention. Flip green (Y), Swap red and green and Add gamma perform different operations; choose them for the source map and inspect the rendered result.