Normal vs Bumpmap

[NicolasW]

I saw in another post it's not planned to add normal map support, normal maps are not just for simulating "bumped" surface, here are some examples of materials that can't be made without.

I built both the height and the normal for each example, the normal accurately represents the slope from the height map.
The images are rendered in vray, reflection color and glossiness are uniform, only the "bump" channel is changed.

Brushed surface



Galvanized



Flakes



Scratches

[adams]

Maybe map the reflection slot?

[NicolasW]

There is no reason to modify the reflection value, it's the same matter with the same properties. Only the micro facet orientation is changing.

[adams]

You haven't tried reproducing in FStorm - these are all rendered VRay right? I really looked at the galv of the bat and thought that would be reflect mapping introduced - at least I would probably try that first (galv really isn't a bump it is very smooth - think galv sheetmetal etc is what that is meant to look like). Creating clean brushed or scratches render should not be an issue. Guess you have to try in FStorm before say can't be made?

[Zealous]

Respectfully, NicolasW really knows his stuff, it is his job.
Regardless of render engine, a normal map carries different directional information than a bump map, I really hope that it can be implemented into FStorm.

[Karba]

FStorm bump works better than VRay one. It stays sharp no matter what distance and angle view.

[Karba]

One more render

[NicolasW]

Zealous thanks

adams I've tried and I get similar results as with vray, I used vray here to show the difference in the same context.
For the galvanized you are right it's not bump and that's the whole point of using the normal map I made: the surface remains flat but the highlights are affected by the normal directions.

Karba I don't really see/understand how the Fstorm bump is better than vray's. As soon as you disable the texture filtering in vray you get sharp results.
You result for the anisotropic noise are interresting, are you able to get nice flakes/galvanized results ?

[Karba]

Fashion teapot

[Karba]

Here is the scene (registration is required)

[JohannesL]

I don't see why one would want to put the galvanization in a bump/normal map? Aren't galvanized surfaces flat? As of all the reference images I can find shows, the galvanization pattern doesn't affect the angle or shape of the reflection, only intensity?

http://thersic.com/wordpress/wordpre...lvanized-1.jpg
http://www.metalsupermarkets.com/wp-...ized-steel.jpg
http://3.imimg.com/data3/EV/YB/MY-22...te-500x500.jpg

Personally I don't care for normal map support, although one thing that is important is to be able to convert materials that contains normal maps without loosing the normal (bump) since many models that we buy contain normal maps and manually converting normals to bump is a time consuming task.

I guess there is a point of having normal map support, as the link below shows. But personally I have never actually experienced the effect that the image shows (like that the diffuse texture are being bent by the normal direction) and I haven't had any problems replicating any material in FStorm so far.

http://67.media.tumblr.com/13ce3c0e7...gwE1r2xhmf.png

[NicolasW]

If you only look at static photos, yes you won't be able to get why it's important to use a normal map, look at a real life sample and you'll see how the matter reacts to light.

Flat surfaces don't really exist, at macro/micro scale a surface is not flat at all: that's the micro facet theory and that's what you roughly adjust when tweak a glossiness value.
Glossiness/bump/normal are approximations used to simulate the same thing but at different scale.

Regular bump maps are commonly used to simulate macro scale relief, normal maps can be used to simulate the same thing but can do more as I tried to explain in my first post.

It is just not possible to get the same effect as a normal map because both don't provide the same information:
- the bump map just give a height information, the surface "distortion" is computed at run time by making multiple samples
- the normal map directly gives direction information, there is no sense of height in a normal map, just directions

At the end it's up to how far you want to go in therms of realism, if you find tweaking the materials by adjusting non physical values suits you, it's ok.. I'm personally aiming for material definitions that have more controls and are closer to reality.

[adams]

This is an interesting one, but I guess you need normal maps then - maybe FStorm will add compatibility in future. Yes, get the whole how light reacts on different surfaces, and flat surfaces don't really exist, I'm looking at something right now - I think if you are here, we get it. Micro this and micro that, check.

Normal maps would make my life easier for certain things as far as conversion, but I don't think they make that bigger difference in the grand scheme.

The use of normal maps in a typical scene isn't weighted to the normal map, most scenes would contain majority bump maps. Depends on what you do of course, if you are doing close up product design viz, sure custom normal maps would be better and the current workflow, and there are plenty tools that do a great job creating normal maps out there, and engines that support normal maps.

In all honesty, the differences between the pro's and con's of using either/or both, who's really going to notice in majority of most rendered scenes?
There are probably other issues going on anyway in any scene that a skilled eye would pick out long before they actually notice that pretty reality shader! But when that skilled eye does notice this perfect reality shader, the question if it was constructed using a normal or a bump, I would bet that skilled eye could not confirm either/or..

I feel that your first post was incorrect in posting some relatively simple shaders rendered in Vray and saying you cannot achieve this quality using FStorm (using normal map render as benchmark). You obviously know your stuff and didn't even attempt to try and recreate them in FStorm. If you posted a this is Vray render using normal map, and this is same shader recreated in FStorm, see how wrong FStorm shader is, then that seems fair enough.

[Zealous]

I think adams, you may have misinterpreted Nicholas, to be fair his first post was only to demonstrate the conceptual difference between a normal map and a bump map, the render engine it was done on was completely irrelevant. He certainly was not trying to be inflammatory, just being factual and his examples were very good. A bump map in its basic sense is just a singular direction height field map using grey scale information to dictate the height variation. A normal map provides multi directional surface information to provide a different dynamic when viewed at different angles.
It is not about pros and cons, it is just to explain they are different processes.

The trick to photo realism is subtlety, just ask Grant Warwick, so a lot of these finer details really do matter. None of this is an 'attack' on Fstorm at all, in fact far far from it, Nicholas is just helping explain that normal maps can provide a whole load more opportunity to achieve these very important 'finer' details.
FStorm is shaping up to be one hell of a render engine, yesterday I went back to some old projects converted to FStorm and I was blown away (thanks Andrey!), it would be a real, real shame not to provide FStorm with all the extra opportunities for realism that are afforded by the other render engines.

The Fstorm bump map is really great! But it will always be a bump map, a normal map offers us extra opportunities.

[Karba]

I think adams, you may have misinterpreted Nicholas, to be fair his first post was only to demonstrate the conceptual difference between a normal map and a bump map, the render engine it was done on was completely irrelevant. He certainly was not trying to be inflammatory, just being factual and his examples were very good. A bump map in its basic sense is just a singular direction height field map using grey scale information to dictate the height variation. A normal map provides multi directional surface information to provide a different dynamic when viewed at different angles.
It is not about pros and cons, it is just to explain they are different processes.

The trick to photo realism is subtlety, just ask Grant Warwick, so a lot of these finer details really do matter. None of this is an 'attack' on Fstorm at all, in fact far far from it, Nicholas is just helping explain that normal maps can provide a whole load more opportunity to achieve these very important 'finer' details.
FStorm is shaping up to be one hell of a render engine, yesterday I went back to some old projects converted to FStorm and I was blown away (thanks Andrey!), it would be a real, real shame not to provide FStorm with all the extra opportunities for realism that are afforded by the other render engines.

The Fstorm bump map is really great! But it will always be a bump map, a normal map offers us extra opportunities.

You have too high impression about normal map. It doesn't provide anything of that "multi directional surface information to provide a different dynamic when viewed at different angles"
You can always simulate all "normal map effects" by proper height map. Normal map is just a derivative of height map in math terms.

I will add normal map support at some point not because of it has some special abilities, but for material conversion from other renders.