Graphics Reference
In-Depth Information
Note: Using Trial and Error with Settings
It's actually not as unmethodological as it sounds. When experimenting with settings, a good way
to proceed is with the “rule of halves.” Instead of starting with a high (or low) value and changing
it incrementally, begin in the middle. If you need more of the effect, go halfway from there toward
the maximum. Simply repeat. This lets you narrow in on the right value quickly.
A Fresnel value of 0.0 means that reflection works identically from all viewing angles. At 5.0, only faces
that are almost perpendicular to the viewer show reflection. Going with the rule of halves method, I try
2.5, and it looks like that's just where it needs to be. Yeah, rule of halves!
The last thing we need to do is to adjust the Gloss Amount . Gloss Amount in the Mirror panel controls
the sharpness of the reflection. The default, 1.0, creates a perfect reflection. Reducing the value causes the
reflection to blur. This reflection blur costs a little bit of time, so it's worth it to try the material both with
and without it to see if you can get away with perfect reflection. Often you can. Generally, you'll want to
leave the Gloss Amount value at 1.0, but sometimes it just makes things look nonbelievable. Reducing Gloss
Amount to 0.5 (halfway!) was too far, so I bumped it back up to 0.75, which worked nicely.
And finally, remember how we used the dirt texture to vary the specular intensity? That same dirt should
probably affect the reflectivity, no? It's easily accomplished. In the dirt texture's Influence panel, enable
the Ray Mirror channel under Shading and set it to 0.48, the value from the material. Set the material's
base Reflectivity to 0.0 so the values don't interfere with each other.
The Vase: Transparency and the Faked Reflection
The vase will be blue glass. Diffuse properties of the glass will be: a light blue, the Lambert shader, and
an Intensity of 0.6. As this is going to be transparent, it's a little hard to pick an intensity this soon. The
specular properties should compliment the diffuse, so, the WardIso shader, which makes a bright glasslike
highlight, and Intensity at 0.4.
It wouldn't hurt to add the same dirt texture we used on the table to the glass to vary the specular
intensity a little. Add a texture channel and in the selector at the top where you would normally name
the texture, use the browser button to find the dirt texture (which you named appropriately to make it
easy to find, right? Right?). Use Smart Project to add a rapid UV map to the geometry, and set the
Mapping coordinates to UV. Disable Diffuse Color on the Influence panel. Turn on Specular Intensity
influence, and while we're there, enable Normal as well. Keep it subtle, though. The glass isn't window
glass—adding a tiny bit of normal roughness will give it an artisan appearance. In this case, we want the
glass to always have some amount of specularity, say, half the maximum value, and use the texture to
allow it to go the max.
To do this, set the Intensity in the Material properties to 0.2 (half of the original), and the Intensity in
the Influence panel to 0.2 as well.
None of this should be news to you at this point.
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