Hi,
das specular map sorgt für Lichtreflexe. Für Beton- und Holztexturen vorzugsweise in den Hglossiness channel ziehen.
Allgemeines hierzu von chaosgroup, Dmitry Vinnik,
Technical Director
"The physically accurate model of the shader should not separate the specular from reflection. However this is added to the shader in order to add more control to the user.
Since the way vray works, it treats reflectance in two different ways:
direct and indirect reflection. Where direct reflection is a specular component, and indirect reflection is a bounced ray.
Simply put, when they are used together, vray does sortof a blend of direct and indirect specular, when specular is traced from light sources. But when they are separated, user has individual control over the spread of the specular vs reflectance.
A good example would be to eather use a layered shader such as vray blend material and blend few different speculars over top of each other, to simulate effects like car paint, or coated surfaces.
The other way would be to simulate effect of blurred material with sharp highlites, where reflection can be blurred and specular can be sharp." __________________
Und das hier vom Entwickler selbst,Vlado Koylazow:
In nature, hilights are simply reflections of light sources. In computer graphics, there are two ways to calculate this same effect: the one is to make no distinction between lights and other objects, and to just do reflections (what Morbid refers to as indirect hilight); the other is treat lights separately from all other objects, since they tend to be bright and their reflections are important for the appearance of the object and so it makes sense to calculate their reflections separately (what Morbid refers to as specular hilight).
It is important to realize that both methods produce the same visual results, they are just different approaches to the same effect. However, in certain situations the first method performs better, in other situations - the second. By "better" here I mean the amount of noise in the area light's reflection for a given number of samples.
Luckily, it is possible to combine (blend) both of these methods to produce a result with the least amount of noise for the given number of samples. In this case, the final result in the image is a sum of two components - one computed as a regular reflection, and the other - computed as a hilight. When added together, these produce the final accurate result. Of course, this only works correctly if both the reflection and the hilight are computed with the same glossiness value.
For artistic and render speed reasons however, V-Ray allows you to use a different glossiness for each of these effects. This is not physically accurate, but may be useful in many situations.
For car paint specifically, the correct way to do it is to use a VRayBlendMtl material to overlay several materials with different glossiness values.
------------------
Gruß niku & carlos
Eine Antwort auf diesen Beitrag verfassen (mit Zitat/Zitat des Beitrags) IP
Foren auf CAD.de (alle Foren)
| 
