PDA

View Full Version : Normal vs. bump: when to use?



jeric_synergy
12-02-2016, 12:14 PM
This hasn't come up for me, but now that I'm using 3dC I'm wondering:

When is it appropriate to use a Normal map versus a Bump map?

prometheus
12-02-2016, 12:22 PM
http://blog.digitaltutors.com/bump-normal-and-displacement-maps/

MSherak
12-02-2016, 12:44 PM
This hasn't come up for me, but now that I'm using 3dC I'm wondering:

When is it appropriate to use a Normal map versus a Bump map?


I use both at the same time. I use normal maps to get the general surface adjustments and use bump maps to add the finer detail. Normals at fine detail have to be very large maps.

jeric_synergy
12-02-2016, 12:48 PM
I use both at the same time. I use normal maps to get the general surface adjustments and use bump maps to add the finer detail. Normals at fine detail have to be very large maps.
Do you use lower rez maps then for the Bump?

ActionBob
12-02-2016, 03:02 PM
I would posit that it is a matter of distance. If you are doing a hero shot on an object, I wouldn't use either. Normal maps are much nicer than bump, but at any reasonable range (particularly with certain angles), I can spot them a mile away. That said, I would always favor a good normal map over a bump map these days as bump maps are really a legacy thing. Again, it really depends on distance and what "look" you are going for. If it is not intended to be a photo-real asset, then whatever is easiest and resource efficient for you is fine.

With the advent of tools such as 3d Coat, the Quixel suite or Substance painter, you can now simply paint normal maps without needing to bake from a high res asset. However, it also depends on the asset. Normals are great for things like paneling and adding "depth" to things that aren't the focus of a shot; details that you notice in passing or things that would simply take too much time to model - say the pores and dimples of an orange / something organic. But if the camera is held or focused too long, particularly at the wrong angle, those bump and normal shading tricks are revealed for what they are - tricks.

Not knocking them in any way, they have their uses and are essential to for some types of detail, but given the poly-pushing hardware we have available to us these days, I tend to lean more toward actual model geometry.

-Adrian

gerry_g
12-02-2016, 03:44 PM
a bump map can be grey scale ( one channel) a normal map is three channels (RGB) so like for like the normal map is three times the file size of the bump map, I use both together but where as I might take a bump map to 4 or 8k I tend to keep normal maps at around the 2k mark for practical reasons, particularly if I am loading a lot.

MSherak
12-02-2016, 04:31 PM
Do you use lower rez maps then for the Bump?

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Pointing up to response above this for the way you want to go

Andy Webb
12-04-2016, 06:22 AM
The problem I always have with normal maps is whether they need inverting in LW.

I can never makeup my mind as to whether the normal map is working as it should, once I start messing around ir never looks right what ever I do...

pinkmouse
12-04-2016, 06:59 AM
...once I start messing around ir never looks right what ever I do...

Yeah, just like that hollow face illusion (https://www.youtube.com/watch?v=BaofyuCXZ_0). :)

Andy Webb
12-04-2016, 07:44 AM
Exactly :thumbsup:

djwaterman
12-04-2016, 09:14 AM
Has it been stated yet? Well it can't be stated too many times, always make sure your normal map is set to Linear in the image editor.

Andy Webb
12-04-2016, 09:24 AM
Has it been stated yet? Well it can't be stated too many times, always make sure your normal map is set to Linear in the image editor.

That's a must

jasonwestmas
12-04-2016, 10:47 AM
I rarely see the need for bump maps unless the UV seams are posing a problem with the normal map; Making the seam more noticeable with a normal map is sometimes an issue if the unwrap is complex or poorly done. I usually only use normal maps for fine detail anyway if I don't have the time to render super fine displacements. Granted for real time rendering you almost always have to have a normal map unless of course your style calls more just flat texture shading. Which is fine for a lot of games I've worked on. And as mentioned, normal map verses displacement depends on how close the subject is to the camera.

Over time one can get pretty good at spotting an inverted color channel in a normal map. Usually it's just the green channel that needs to be inverted these days.

jeric_synergy
12-04-2016, 11:04 AM
If I use them at all, it'll be via direct creation in 3dC rather than a LW normal bake-- that's just too much tech for me.

Jason, thanks for the info: mostly over my game though! ;)

meshpig
12-04-2016, 11:34 PM
Has it been stated yet? Well it can't be stated too many times, always make sure your normal map is set to Linear in the image editor.

Nice tip :)

Thomas Helzle
01-06-2017, 11:04 AM
Depending on how you generate them, I'd always prefer normal maps.

A bump map is only a greyscale map and is sampled in several spots around the current render point to find out the ramp-direction. This has several drawbacks:
- Only relatively strong changes can be represented adequately, very slow gradients will simply vanish.
- You can't really have a plain area "point" in a certain specific direction - which you can have with a Normal Map.
- You can't have really hard changes, since the nature of the bump beast is the slope - this is why bumpmaps usually look unnaturally smooth when one looks close.
- Depending on the implementation bumpmaps can be slower to render, since several samples have to be taken.
- The good thing is, that it's easy to create bumpmaps.

Normal maps on the other hand are XYZ direction vectors encoded into RGB.
- Each pixel contains a defined direction in which the point in question is supposed to point, so only that one point has to be sampled.
- Hard changes are possible.
- Large, continuous areas can point into an arbitrary direction.
- You can have slow changes in direction over large areas with no problem if you use floating point normal maps.

This of course mostly applies if you aren't just using some bitmap to normal converter but either paint the normal map directly or bake it from a high-res model.

Cheers,

Tom

jwiede
01-06-2017, 11:52 AM
I'm interested in how difficult it would be to add parallax mapping/RTM/VDM (https://www8.cs.umu.se/kurser/5DV051/HT11/lab/parallax_mapping.pdf) (that's a basic ref, there are other papers as well) support to bump and/or normal maps in LW, as were added to C4D in R18 (https://www.microsoft.com/accessories/en-us/products/keyboards/natural-ergonomic-keyboard-4000/b2m-00012). The impact on quality of bump/normal map appearance is greatly improved, yet still a very substantial display perf savings over "proper" displacement mapping (benefits and requirements vary by approach).

MSherak
01-06-2017, 02:44 PM
I'm interested in how difficult it would be to add parallax mapping/RTM/VDM (https://www8.cs.umu.se/kurser/5DV051/HT11/lab/parallax_mapping.pdf) (that's a basic ref, there are other papers as well) support to bump and/or normal maps in LW, as were added to C4D in R18 (https://www.microsoft.com/accessories/en-us/products/keyboards/natural-ergonomic-keyboard-4000/b2m-00012). The impact on quality of bump/normal map appearance is greatly improved, yet still a very substantial display perf savings over "proper" displacement mapping (benefits and requirements vary by approach).

http://dpont.pagesperso-orange.fr/plugins/nodes/Additionnal_Nodes_2.html

Relief Map

Greenlaw
01-06-2017, 03:01 PM
Generally I like to use normal maps but sometimes I'll use both, normal and bump, if I need a lot of detail.

When using both, I'll use normal for broader surface detail where you really need to see how the light and shadows move over the surface, and a bump texture for tinier details, or to break up the light on the surface.

I find that small bump textures applied too strongly can add unwanted noise to the surface and require stronger AA, so you don't want to push it too far. If bump becomes a problem, sometimes I'll set up a distance to camera control to reduce the amount of detail as the surface moves away. This can look nicer and may even speed up the render by simplifying the AA in the distance.

jeric_synergy
01-06-2017, 04:26 PM
Very interesting: is it not a lot easier to find bump maps than normal maps, for things like a little added texture???

Greenlaw
01-06-2017, 05:44 PM
I like to use a program called Shader Map Pro (http://shadermap.com/home/), which can generate normal maps from bitmap images. It will even generate other useful maps like occlusion, diffuse, spec, etc. The quality depends on what you feed into it but I can't count the hours this tool has saved me over many years.

For example, convincing building facades from photographs are a snap to create. I've made entire city blocks for TV commercials using this tool. No, it's not a true substitute for modeling everything out but when deadlines are tight and manpower is short, it's a great tool to have.

It's super useful and super cheap too.

jwiede
01-06-2017, 08:15 PM
http://dpont.pagesperso-orange.fr/plugins/nodes/Additionnal_Nodes_2.html

Relief Map

Anyone know if DP Kit's Relief Map node works on Mac LW2015.3? The UB plugin version predates LW2015, I can't recall ever trying this before, and am not seeing expected output using 2D bricks procedural input as bump & height (per ReliefMap example in description). Instead of getting a relief map normal map, I just get all black even after F9 (that produces bricks w.r.t. color, suggesting projection is correct, but nothing else).

I'll post a scene when I get a chance, I want to try first using simple UV-mapped textures instead of procedurals.

dpont
01-07-2017, 12:06 AM
...I'll post a scene when I get a chance, I want to try first using simple UV-mapped textures instead of procedurals.

I hope you are not using UV Mapping nodally
this is a limitation of LW nodal system,
not possible to pass uv coordinates through a node tree
in Relief Map UV mapping works exclusively
in panel settings.

Denis.

jeric_synergy
01-07-2017, 12:13 AM
I like to use a program called Shader Map Pro (http://shadermap.com/home/), which can generate normal maps from bitmap images. It will even generate other useful maps like occlusion, diffuse, spec, etc. The quality depends on what you feed into it but I can't count the hours this tool has saved me over many years.
Thanks for the tip, Greenlaw! Valuable info! :bowdown:

jwiede
01-07-2017, 03:35 AM
I hope you are not using UV Mapping nodally

Nope, tests were done using cube, procedural bricks2d texture, cubic mapping. As far as I can tell, the flow shown should work, but no matter what "height" input I gave, the preview for relief map's normal channel never showed other than black. Settings as per pictures, likewise with flow. Using the example on this page (http://dpont.pagesperso-orange.fr/plugins/nodes/nodes/ReliefMapping.html) as guide, I believe I should see _something_ in relief map normal preview when feeding either alpha or color (using black and near-white colors) into "height" input, yet do not. MacOS 10.12.2, LW2015.3 UB64, DPKit latest for MacUB.

Note: bricks2d preview in flow shows color channel out, white-looking bricks2d preview is alpha out, mostly-black bricks2d preview is bump(normal) channel out.

135512135511135510135513135514

I'm probably missing something obvious, but I'm not seeing the issue, and starting to wonder if it's either due to running 6/2014 DPKit in LW2015.3 or LW2015.3 itself. I can provide scene+object if needed, but object is simple cube, and scene is default plus cube, then add node flow surface (and enable). If I feed color to surface color etc., shows up exactly as expected during F9 and VPR of cube (and after F9 relief map node still preview remains black).

Any help appreciated!

dpont
01-07-2017, 04:01 AM
...the preview for relief map's normal channel never showed other than black. ...


Relief Map surfacing or nodal preview is not working for several reasons,
especially in its classic usage because effect is tied to a geometry preprocess.

Denis.

Ztreem
01-07-2017, 04:57 AM
I'm interested in how difficult it would be to add parallax mapping/RTM/VDM (https://www8.cs.umu.se/kurser/5DV051/HT11/lab/parallax_mapping.pdf) (that's a basic ref, there are other papers as well) support to bump and/or normal maps in LW, as were added to C4D in R18 (https://www.microsoft.com/accessories/en-us/products/keyboards/natural-ergonomic-keyboard-4000/b2m-00012). The impact on quality of bump/normal map appearance is greatly improved, yet still a very substantial display perf savings over "proper" displacement mapping (benefits and requirements vary by approach).


As LW supports cgfx shaders, can it be possible that there is a parallax shader that you can use in LW?

erikals
01-07-2017, 10:41 AM
I like to use a program called Shader Map Pro (http://shadermap.com/home/), which can generate normal maps from bitmap images. It will even generate other useful maps like occlusion, diffuse, spec, etc. The quality depends on what you feed into it but I can't count the hours this tool has saved me over many years.

For example, convincing building facades from photographs are a snap to create. I've made entire city blocks for TV commercials using this tool. No, it's not a true substitute for modeling everything out but when deadlines are tight and manpower is short, it's a great tool to have.

It's super useful and super cheap too.

yes, Absolutely, a must i think, also check out >

Knald    $100
MindTex    $20
nDo2    $100  PS PLUGIN
PixPlant    $50  PS PLUGIN
ShaderMap    $50
Bitmap2Material    $100
CrazyBump    $300

jwiede
01-07-2017, 02:41 PM
Relief Map surfacing or nodal preview is not working for several reasons,
especially in its classic usage because effect is tied to a geometry preprocess.

Yeah, doesn't appear to be just preview, if nodes are enabled it just yields 100% black output for object as well. Oh well, thanks for help with it!

Can you say approximately which nodes/shaders/elements in last UB Mac release of DP Kit won't work with LW2015(.3) UB Mac?

BTW, I tried to send you a PM but your inbox is full.

- - - Updated - - -


As LW supports cgfx shaders, can it be possible that there is a parallax shader that you can use in LW?

Coding up a cgfx-based parallax shader should be trivial, there are plenty of reference examples. Problem is, cgfx won't really help with improving _rendered_ bump/normal map output.

Ztreem
01-07-2017, 05:54 PM
Coding up a cgfx-based parallax shader should be trivial, there are plenty of reference examples. Problem is, cgfx won't really help with improving _rendered_ bump/normal map output.

That's right cgfx is only for opengl and not for rendering. I don't use it myself, I just remember some normalmap preview by using cgfx.