Materials in Corona (Part.2)

In this section, we are going to play configuring concrete or wood slats PBR for our walls in combination with other materials for the same room without detaching the asset planes thanks to Corona Multi/ Sub-Object feature.

This is the Part 2 of 3 Posts.

Part 1: https://handytales.com/blogs/tutorials/materials-in-corona-part.1/

Point 3: Applying different Materials within the same object

Time to go back to our test studio to play with this Multy Texture feature…

1) We select the entire object (room) by pressing Ctrl+A (All becomes red) and we go to plane mode within the Edit Poly Modifier.

2) We assign an ID for ALL the planes of the object (room). This can be done by selecting all the planes and setting the value “1” within the Set ID and Select ID fields (Polygons Material ID).

3) We select our special wall and we assign it another ID (“2”). This change is applied automatically…you do not need to submit/ toggle anything apart from declaring the new ID.

4) We select the third ID for the window openings as these normally have a different type of material.

Now we have three IDs assigned to different sections of the room, therefore, is time to assign a new node that will allow us to set different materials within the same object (room) and the guy is the Multi/Sub-Object feature.

Select Discard Old Material.

This new material brings a new panel for us to define sub-materials for each of our IDs….pretty cool!.

We are going to define the material that will cover 3/4 walls. Select “None” from the first row and choose CoronaMtl.

We have our first default material in the first row but we need to add materials also to the next two IDs (openings & special wall).

Rather than start doing the same over and over again, you just need to drag the material of the first line into the second and third. The duplicity needs to be defined as Copy due to the materials will be different.

We apply the configured material to our room.

We define the material for the windows openings (ID 3) with an Albedo/ Color above 180 (in our case 210) then we tend to decrease the Diffuse Level to 0.8.

Maximum on Reflection Level (“1“) and 0.62 for Glossiness to close it to matte material.

Point 4: Adding Concrete by using PBR materials

We “Go to Parent” to select the second ID; our new concrete wall.

This material will be configured by our concrete PBR texture (ID 2). The PBR brings Color, Displacement, Normal and Roughness maps.

At this point, we set the Color map on Diffuse and now we look to add the Roughness in the Reflection Glossiness. Select CoronaBitmap to load your map.

The above panel pops up to look for the Roughness map that will end in the Bitmap pannel.

Once applied, it would be worth adding CoronaLight close to the wall to see how the material behaves in a more controlled environment. This light can be levelled through the Rest light toggle (LightMix tab). Remember to dim down the Skylight to bring prevalence to the bulb.

We can see in the render the reflection is very flat…If we want to make it more reflective we can apply the CoronaColorCorrect node to bring more Brightness.

Access the Roughness map through the M toggle. Press the CoronaBitmap and apply the CoronaColorCorrect node. Remember to select “Keep old map as sub-map” when Corona asks you to Replace Map.

Brightness is increased by 0.3 (1 is the max value for this box) and we can see a better reflective index in the wall.

We already added the Displacement map and we want to explain how to add the Bump map with our Normal map.

Click in “No Map” and link the CoronaNormal node.

Within this node add the Normal map from your PBR by using CoronaBitmap. In case you have more than one Normal map in your material (DX, GL…), I tend to use the GL version (Open GL) as it is more compatible with most of the tools.

Now we have our 4 guys connected, but the render does not seem right as is less reflective than expected .

Got it!, I forgot to check in the CoronaNormal node the “Add gamma to input” toggle. This option brings back the Brightness we were looking for!! …now the wall damage is now more realistic.

In case the disposition of the wall material needs to be corrected, please remember to add the UVW Map Modifier on top of the Edit Poly to be able to play with the UVs. In case you do not know the map’s height expected by the material designer, simply access your map properties to know its resolution and divide its width by height to know the ratio that can be applied in the Height of the UV.

One of the inconveniences of this process (materials per ID) is the UV modifier that basically affects all the IDs. In case we want to avoid this the wall must be detached.

I added to our wall some wood slats by using the same explained procedure. I wanted to depict another possible problem with this specific material based on IDs. The slats, when they cross the other planes simply describe a perfect vertical line which does not seem very realistic. I tried to increase the displacement map but the result does not produce an optimum result.

I finally detached the wall from the rest of the room planes to show what you can achieve. I tested the Bump and I got better results with -5 as value. The Displacement was defined within a range of [0.2mm(Min. level), 10mm(Max. level)]. The Brightness is left as 0.7. It is hard to see it but we achieved a bit of profile from the wood slats in the corner .