Further research into shader’s for mental ray
Here is a link that I found that intrigued me into thinking how the effect in the image was achieved. Although image is titled mushroom, I don’t see the resemblance, possibly due to the angle it has been shot. Maybe the purpose of shooting at this angle was to show off the texture of the cap of the mushrooms.
In the first image provided I think that they have obviously added a bump map to create the bumps on the surface of the object. I definitely think that a point light has been used from the top angle as the sides appear in a much darker shade. I don’t think a spot light has been used because there is no shadow been casting on the floor nor on the base which the mushroom is resting on. However the sides that are darker in shade should have turned out black if just a point light was used. Therefore I believe an ambient light must have been used on a low exposure to lighten up the dark sides. I can definitely see that ray tracing has been used to cause the base and mushroom to reflect of each other.
Above is a link that demonstrates the effects of each light so I know what light will create shadows, soft shadows or no shadows.
This third experiment of the artist is ideal for the type of effect I desire. Although instead of rust my character will have cardboard parts, the contrast between the matte and reflective shiny areas is the effect I am hoping to achieve. The basic thing the artist has done is to provide an environmental texture in both images to support the ray tracing effect used to enhance the reflections. I know that ray tracing, point light (and possibly ambient light) and bump mapping has been used but I don’t understand how a matte material and a shiny material can exist without unintentional influence on each other. This is what I want to achieve with my character.
I have thought about something! The environmental texture can also be applied in mental ray>indirect lighting>Image based lighting. This would allow the a desired image to be imported and use the light source from that image to light the character. Of course to perform this final gathering and global illumination would need to be ticked in the same tab.
Now to understand how to achieve the contrast between metal and a matte material, I will watch the following video. In the video it suggests to download a plug-in called NDO2. However I don’t think that plug-in is necessary because I can experiment the same way in Maya the way he is adjusting it in NDO2. I found it useful to know that the image adjustment curves can adjust the black and white levels to create a better contrast for the bump mapping.
Maps: Diffuse, Normal and Specular
Apply diffuse map to Blinn>Colour
Apply normal map to Blinn>Bump map (Select tangent space normals)
Apply specular map to Blinn>Reflectivity (Drag also to specular colour from work area using MMB)
Turn up reflect colour
Metal has lower diffuse value and high specular
Adjust eccentricity and specular roll off
“Environment reflection is what brings out the metal texture”
Furn ball>Add mesh attribute>New(mesh node)>Reflection map>Environmental background