Wow, I get back from the weekend to find loads of replies here, my PM inbox flooded, and my email straining from all the response
Thanks for all the ocntributions and debate so far people - this is what it’s all about!!
dark_lotus, Canofworms, l_farley13_l, d_hansbury, Sevarf2, Aura, wgreenlee1, Hookflash, Phil “Osirus” - thanks for all the postive and encouraging comments
HapZungLam - I will be putting together a bit on painting specularity and reflection maps as soon as I have a bit more spare time again. In the meantime, just read the tips that I put together, and see what you can use from that.
The overall amount of spec that skin has is tricky to say. What I always do is make a spec map using shades of grey, load it into my spec channel, and then just adjust the spec amount until it looks right.
For wood (and anything else actually), I tend to always use combinations of both reflection and specularity. As I said, I find that I, personally, get the bets results when I use both.
Fingerprints - nah, you don’t have to go and put them onto absolutely everything. However, I do find that for things like glass, it looks great. I know that in reality everything we touch does get fingerprints on it, but I guess most substances absorb the oil from the prints, so that they are no longer as visible.
To add fingerprints to your spec and ref maps, just paint them onto the maps - as I explained, the best way to do that is to make brushes in Photoshop that look like fingerprints. Then you paint them on, making those areas darker.
road - Max’s material editor is pretty cool, yeah, but for best results, it’s advisable, in my opinion, to use the raytrace materials - they allow more options, and give you greater control in terms of setting up surfaces which act the way they should in the real world.
boomji - hehehe what a funny story! I love that intro! And yeah, I’m a true Leo to the end…
Goon - as I explained above to HapZungLam, fingerprints are great, but indeed are unnecessary unless it’s for glass. Looking at my computer monitor, I see that although it has been recently cleaned, there are still oily smudges and fingerprints on it, so if I were to make a CG computer monitor, I would most certainly add the fingerprints to the texture. Something else that would work very well in conjunction with the fingerprints would be to use some gradients along with them to give that oily array of colours when you see the fingerprints from some angles. Now THAT would look cool…
But yeah, with most other surfaces, the fingerprints do disappear rather quickly, so it’s mostly unneccesary to put them there. Unless you are a real detail freak…
dwkim - thanks for that info on rendering. I do know about some of that stuff that you mentioned, but I thought not to include it because I didn’t want to confuse the texturing issue with the rendering issue at this point - because I wasn’t writing about reflection environments, just reflection maps for the objects reflection channel. However, I am glad that you did post all that so that people can find that out once they have read the actual workshop
CitizenVertex (and also Galo and Grooveholmes)- I knew that this debate would start, it was one of the reasons why I posted this in the first place. The whole specularity VS reflection debate is a fascinating one, which is why I posted both sides of the equation and left it up to the readers to experiment and decide for themselves which methods work for them.
“Specularity allows you to vary the angle at which light is reflected creating a hotspot of the surface.” - yeah, that is why I mentioned anisotropic specularity, because that is the function you use for altering the angle.
I do disagree with you on the point of specularity being a reflection of light in general though. There is no such thing as “a general reflection of light” - the light came from somewhere, the lighsource, so it would stand to reason that the reflection is therefore always of the source, however distorted or blurred it may be.
Like I said, I personally find that a combination of the two gets great results, but I do believe that specularity in its 3D incarnation is, technically speaking, a fake.
Specularity, in this sense, does not actually exist in the real world - it is a phenonmenon of artistic recreation of objects. As I explained, the term specularity refers to specular highlights, which are actually reflections of the lightsource. Therefore, it’s logical that there would be a debate as to the use of specularity in CG, when in terms of reality, reflection is the one that should be used.
However, as far as I am concerned, because all of CG is a big fake, I don’t see why I can’t use specularity - if it looks right, then I use it. And 99.9% of the time, I find that using specularity does give me the look I am after, so I use it.
Marcel - “A specular reflection of a window still gives a round highlight, not a rectangular shaped one.” Yup, you nailed it right there. That is exactly what I am talking about Thanks for clarifying it so simply.
NanoGator - thanks for that in-depth analysis. Some great info you have written there. Don’t worry, you didn’t kill the thread at all - your contribution was valid, and I’m sure everyone appreciates it!
psil - I do want to put together a workshop on more Photoshop-specific stuff, but I will only do that right at the end. I want to go through all the specifics of the aspects of texturing first, and then go into their practical creation.
frog - “Those plain round highlights are one of the main reasons that so much CG makes the world look as if everything is made of plastic” - so true. That’s why I use both - specularity does tend to make things look plasticy because of the round shape of the highlights. However, the reason I discussed the BRDF shader is because using anisotropic specularity does tend to make the highlights a lot less round, and thereby a little more realistic.
That said though, I do think that specularity has to be used carefully and in moderation to ensure a realistic look at the end.
playmesumch00ns - thank you so much for all that! Unfortunately, I do not know a lot of the details regarding that more technical stuff (such as Blinn and Phong shading models), and I ws hoping that somebody would post a bit about it all.
“But, as (i think) Leigh neglected to mention, we must then include some geometry to represent the light source.” - oops you got me hehehe I did forget to mention that… Although I would think that it would be a pretty obvious thing to do. I always have luminous objects floating around where the lights are to represent the light sources - works like a charm.
Thanks for your explanations!