Back to Course Main Page

Bump and Normal Maps: Features and Workflows with Mental Ray
This webpage is designed to set about showing the Mental Ray user how to connect together bump and normal map nodes into various shaders using Mental Ray. For the purposes of this demo, Maya 2009 was used, running on an Intel-Mac Quad Core with OS 10.5.

1-How to Connect the MIA_Roundcorners node:

The Purpose of the MIA roundcorners node is to provide beveled/chamfered edges for a hard surface polygon object (****This node does not work well, and is not recomended for use on very smooth organic surfaces as the result will look faceted and no longer smooth*****). Here is an resulting image from one such test of the MIA_roundcorners node:

Without adding any extra geometry to this model, the MIA roundcorners node produces a slick looking beveled edge. Here is how to impliment it. First, I will start with a basic cube:

Next, I will scoll down in the hypershade to the Mental Ray Textures section and I will create a mia_roundcorners node, applying it to the bump map slot of the blinn.

When the node is first connected, you will not notice any change to the profile of the mesh. This is due to two factors. One is the Radius, the other is Bump Mode. The Radius controls the amount of rounding on each corner, where as the Bump mode is value with inputs from 0-8 (whole numbers only) which alter how an addtional bump map can be used to composite with the roundcorners as a daisy-chain. Here we see the defaults, with as expected, no change in the appearance of the model:

By Altering the radius to value of 0.5, notice how I can round out the corners!

2-How to Connect a Regular Bump map AND the MIA_Roundcorners node at the same time:

By Adding in Bump 2d node (from the Maya General Utilities) into the Bump section of the MIA_roundcorners, I can hook up an extra map to render with the roundcorners feature.

Here is what the connections look like in the hypergraph. The Checker texture flows into the bump2d node, which connects to the mia_roundcorners, which then flows into the Blinn.

However, there is still no checker bump on the surface, only the rounded corners. This is because of the Bump Mode value discussed earlier which is still set to "5".

By switching that value to "0" we will get the correct results, as we will see in just a bit:

3-How to Connect a Regular Bump map AND the MIA_Roundcorners node at the same time to an MIA Material:

To demonstrate the effects of the roundcorners+regular bump map, we will take the demo one step further by switching our Material from a Blinn to an MIA_Material. ***Authors Note: While I am using an MIA material, a Blinn would work fine. I'm just trying to show several things at once.****

So here I have created an MIA_Material. In Maya 2009 however, there are THREE DISTINCT CHOICES for the MIA_Material. There are:
MIA_Material
MIA_Material_X
MIA_Material_X_Passes

The basic MIA_Material does not have any slots to input a bump map (and first appeared in Maya 8.5)
The MIA_Material_X_Passes is new to Maya 2009 and is used in conjunction with the new render pass functionality, which is beyond the scope of this demo
We will choose the MIA_Material_X (first appearance Maya 2008), which has slots to handle bump maps. Here is what our network looks like:

We will connect the roundcorners node into the Overall Bump section of the MIA_Material.

However, when you do this, if you had set your bump mode to anything other than "5" (Zero in our case), this will now be reset automatically and driven by the MIA_Material. This is not what we want:

So, lets Right click on the words "Bump Mode", and choose Break Connection from the marking menu.

Then we can reset the value to 0:

Here is a Render. Now we have both Rounded corners, and a checkered bump map!!!!

While we have hooked it up this way, we can also use a differnt method to get the same effect. Take the bump2d node out of the MIA_roundcorners and hook it up into the Standard Bump Section fo the MIA_Material, and you will see the exact same thing:

4-Connecting Normal Maps to MIA and MISS Materials (new to Maya 2009)

I mention this only because these features used to not work prior to Maya 2009. We can now hook up a Normal map through the Standard Bump node in an MIA_Material:

Or, we can hook it up to the Bump node in the Miss_Fast_Skin_shader

The proof that it works can be seen in the animated GIF below. We see the image change when we alter the settings because when set to use as "Bump", the purple colored normal map (which is a low intensity map of tree bark) is rendered as if it were a desaturated height-style bump map. When we switch to use as "Tangent Space Normals" the map is interpreted for it's correct color values which indicate slope. The fact that we see a difference at all is proof this new feature to Maya 2009 is working correctly!