Textures Vs. shaders

Started by TheBadger, January 07, 2014, 09:22:45 pm

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TheBadger

Hello,

I have a general, probably vague question about deciding between using image textures and shaders for models used in TG.

Very curious if there are any, mostly certain things we can say about it, that would usually be true. For example, "I would never use shaders to texture a jet" (I don't know if thats true, just asking).
Or, "If a building is made of sand stone, I would really want to try to texture that in TG rather than paint an image map in another program."

Like I said, general and vague. But only because there is not a lot of posting on this over all.

Also curious if maybe we should think about a materials sticky, like the clouds and terrain. Where people can post and easily find shaders set up for use with models. It seems to me to be a different thing in the end, from shaders for a terrain. THough made from the same nodes.
I know that others have made these kinds of things and posted images with them in use. And If I can get a better sense of the general topic I will be making some too. Really no reason not to share it, that I can think of.

Maybe someone is going to think or say the default, "every scene is different", and "it depends on what you want to do". But really if by now we cant make some simple rules of thumb on these various topics, then this is really neither art or science. And much more like chaos; "Painting with a tornado"

I am just guessing right now, but I think its safe to say that using shaders to detail a model would really work best on high polly? So for a wall, where the stones or bricks are real geometry, and you just want to add color variation and a little displacement? Is that a mostly fair statement?

Thanks for any facts that can be shared. And any help with a good way to think about approaching this in general.
It has been eaten.

j meyer

There are 2 things I want to mention spontaneously.
Since you are into animation you should consider what would
happen with procedural shaders when moving an object.

And we don't have cavity or ao shaders so there is no easy way
to get folds or cracks and crevices darker and things like that.

I hope that starts some thinking of your own and maybe even
a conclusion of yours. ;)

TheBadger

Hi,

Wouldn't the folds and crakes be lighter or darker naturally, based on the natural light, If the folds and cracks are real geometry?

Its to soon to have a conclusion of my own. I need to make many more models yet. And then try each one each way.
It has been eaten.

j meyer

Quote from: TheBadger on January 08, 2014, 05:07:39 pm
....
Wouldn't the folds and crakes be lighter or darker naturally, based on the natural light, If the folds and cracks are real geometry?
....


Judging from my personal experience,no,not really.

Oshyan

Yes, they would be, at least if you were using GISD (in Terragen 3).

- Oshyan

j meyer

Oshyan,I've tested that first and it is only true (to a certain degree)
for the parts that are in shadows as far as I could see.
And that goes for real stuff to (to a certain degree again) and that's
why artists/artisans almost always "cheat".Think of make up,set painting
and so on.

Oshyan

If there is real geometry there for the GI system to work with, and GI settings are reasonable (i.e. not super low), then GISD should be darkening cracks, crevices, etc. regardless of whether the object as a whole is in the sun. Any "crevices" that are in the geometry *are* creating shadow (or would be in real life), even in the sun. If they're not shadowing (i.e. there is light inside them), they shouldn't be darker, right?

- Oshyan

j meyer

Sure.
But will it give you a pleasing result? (image wise,not physical correctness wise)

Oshyan

Depends. It's all speculation until you try. ;) In my tests the answer to your question is generally "yes". If your experiences have been otherwise, perhaps post some examples?

- Oshyan

j meyer

January 09, 2014, 01:58:34 pm #9 Last Edit: January 10, 2014, 10:11:15 am by j meyer
I didn't keep them,because they where all tests for some object and served
to test other aspects,too,while still sculpting on the object.
But I'll try to render some examples in the coming weeksdays,can't say exactly
when,am busy with lots of other stuff at the moment.


Edit:should have been days not weeks,sorry.

TheBadger

Hi

Examples would be really nice.
I realize I need to do my own testing like you guys do. But I really get lost is the minutia of all this and as a result am not finishing projects.

If its convenient and FUN, for anyone to, and they even have time, some kind of visual way of showing do's and don'ts would be very helpful... Settings, anything on the subject that would help make our efforts turn out better, basically. Anything people feel like sharing.

I do understand that time is money, and no one gets paid to share their knowledge. So I offer a humble thank you. And am very glad that there are so many people here who take pleasure in these things as I do.

As for me, if I have to do all the same testing that the more experienced users and 3D artists here have already done, I am sure to starve to death before I finish anything. There is probably many many years of cumulative knowledge between members here. And who on their own could be equal to that?.. Definitely not me.

I am continuing to slowly push ahead though. I will share anything that seems like it would be interesting or useful. Its hard for me to know what that would be right now though ;)

@ J and Oshyan.
I usually listen pretty closely when you guys are talking (particularly when your talking to me) So I really listen when you or other advanced users disagree on something. Because thats when things tend to really get explained/shown/demonstrated. Thanks for discussing it in the open.
It has been eaten.

j meyer

Just wanted to add that our little discussion above relates to
Ambient Occlusion only,so far.I had also mentioned cavity originally
and that can't be done with GISD of course.
My remark about artists cheating relates to cavity,too,not
just AO,though.(just to be sure everyone can follow)



j meyer

Finally found some time yesterday to render the examples.
GISD is default.AO-map is a quick and dirty one,thus exaggerated.
I would not use it that crude,but to illustrate the difference it
should be sufficient.

[attach=1]

[attach=2]

In these examples the model is just gray,now imagine this with a
diffuse texture,painted or procedural,and the benefit/advantage of
using AO-maps (and cavity-maps) should be clear.
Not necessarily with regard to photo realism,though.
But you can emphasize some features that would get lost otherwise.
Like cheating with make up or set painting or painting in general and
of course in addition with lighting,like fill lights and reflectors and
so on.Most likely there is other stuff I forgot to mention or don't
know of,but I hope you'll get my point anyway.


yossam

Where do put the AO map in Terragen?

j meyer

I use to combine it with the diffuse/texture map before importing to TG
and apply it as colour image to the default shader.
But you could load it to an image shader as well and combine that
with your texture either with or without merge shader,for example.