|
|
Normal maps..and normals in general
About Truespace Archives
These pages are a copy of the official truespace forums prior to their removal somewhere around 2011.
They are retained here for archive purposes only.
Normal maps..and normals in general // Archive: Tech Forum
Post by rjeff // Feb 28, 2008, 5:08am
|
rjeff
Total Posts: 1260
|
I feel that as a 3d artist I need to know what this is. Please excuse my ingnorance in this but I would like to know what are normal maps? |
Post by Jack Edwards // Feb 28, 2008, 5:35am
|
Jack Edwards
Total Posts: 4062
|
Normal maps are like bumpmaps except they are in color with the color values telling the engine the direction of the normal vector at that location in the texture.
Check this out:
http://www.crazybump.com/
:D |
Post by spacekdet // Feb 28, 2008, 5:38am
|
spacekdet
Total Posts: 1360
|
Some resources to strengthen your knowledge base:
3D Glossary (http://www.computerarts.co.uk/downloads/3d__and__animation/the_3d_world_glossary) (PDF) @ 3D World Mag
3D Glossary (http://www.webreference.com/3d/glossary/) @ Webreference
Normal definition (http://www.webreference.com/3d/glossary/normal.html)
Normal Mapping tutorial (http://www.highend3d.com/maya/tutorials/texturing/229.html)
A longer tutorial on defining and creating (http://www.bencloward.com/tutorials_normal_maps1.shtml) normal maps here
and the wikipedia entry (http://en.wikipedia.org/wiki/Normal_mapping) |
Post by rjeff // Feb 28, 2008, 5:56am
|
rjeff
Total Posts: 1260
|
Thanks space..I will read that. |
Post by TomG // Feb 28, 2008, 6:07am
|
TomG
Total Posts: 3397
|
A normal is a vector that is perpendicular to the surface - in other words, it says the direction that the surface is pointing in at that particular place on its surface.
They are used in rendering, in order to calculate how light is falling on the point on the surface - once you know the direction the surface is facing at that point, you can calculate how the light falls on it.
A normal map is a way of using an image to define / adjust the normals. It is applied over the model in the same way as a texture or bump map. Note that a bump map adjusts the height of the point on the surface for lighting calculations, but the normal remains pointing the same way - this means bump maps are never quite entirely convincing in their results.
A normal map gets much more convincing as the place on the surface is made to point in a different direction, and so interacts with the lighting differently.
Normal maps are often used to put high detail on low poly models. A high poly version is made (eg lets say clothing, with wrinkles and pockets and all sorts of details. From this, a normal map is generated, an image that contains the direction the surface faces at each point on the surface.
This can then be applied to a low poly version without the pockets, wrinkles, etc. Now the low poly surface interacts with the lighting just as if there was a pocket there, or a wrinkle there, when in fact there is no such geometry. This is particularly done in games and other applications where real-time rendering is required, since reducing the actual geometry reduces the memory and processing requirements, and lets you have the effect of a high poly model without the related processing and memory cost.
HTH!
Tom
EDIT - Note that tS7.5 is capable of both using normal maps in its real-time and offline rendering, and of generating normal maps and a simplified mesh at the same time, for making a low poly version of a mesh with normal map included (or you can remove the normal map from the result and apply it to your own models if you prefer to create the low poly version yourself, or if your normal map has a general application, eg you make a complex high detail terrain and make a normal map to apply to roughen up surfaces and landscapes without the need for all that geometry). |
Post by rjeff // Feb 28, 2008, 8:19am
|
rjeff
Total Posts: 1260
|
Question then..is a normal map a colored texture map with no black and white for height? Or is there more to it than that? |
Post by clintonman // Feb 28, 2008, 8:30am
|
clintonman
Total Posts: 304
|
I think a simplified explain is that a normal map is like a bump map with direction information defined by the color. |
Post by rjeff // Feb 28, 2008, 8:44am
|
rjeff
Total Posts: 1260
|
interesting..I will have to see if there are any tutorials in kadets info that will give me some more detail..thanks guys |
Post by jamesmc // Feb 28, 2008, 8:47am
|
jamesmc
Total Posts: 2566
|
I specialize in making abnormal maps.
One never knows which direction they are going to point or what color they will be. |
Post by TomG // Feb 28, 2008, 9:52am
|
TomG
Total Posts: 3397
|
A normal is a 3 vector - it has a component for size in x, y and z directions. Taken together, these three values define an overall direction in space.
Now, color is also a 3 vector, in this case r,g,b. So it makes image files a handy place to store normals! In a normal map, the r,g,b values are in fact unrelated to color. Sure, a 2D image program will display them, but that is not what they are for.
Instead, they are really to be used as x,y,z values that will define a direction in space. Storing them in an image is just convenient, since color happens to use the same 3 vector approach :) No need to make a new file type! Then the same mapping process can be used as per texture mapping / UV.
So there is no white or black (which are 1,1,1 and 0,0,0 vectors respectively) for height in normal maps. It contains no height information at all, just the information for the direction the normal points in at any given location on the surface. You could use a bump map and a normal map to have both height and normal facing information incorporated.
HTH!
Tom |
Post by v3rd3 // Mar 3, 2008, 12:23pm
|
v3rd3
Total Posts: 388
|
Thomas that is a wonderfully succinct and educational explanation. thanks |
Post by TomG // Mar 3, 2008, 12:33pm
|
TomG
Total Posts: 3397
|
Glad it helped! Thanks for the feedback!
Tom |
Post by brotherx // Mar 4, 2008, 11:06pm
|
brotherx
Total Posts: 538
|
FYI, The NVidia plugin for saving normals also works within paint shop pro XI but you have to go to the paint shop pro directory and copy the files from plug-ins to plugins. Other than that, perfect.
I always thought there was something a little more complicated to this...I love the real-time preview in workspace. |
Post by butterpaw // Mar 5, 2008, 10:01am
|
butterpaw
Total Posts: 831
|
Thanks Jeff, for asking and thanks everyone else for answering .. this was mysterious to me .. and now .. light on the subject .. excellent! ;) |
Post by prodigy // Mar 5, 2008, 11:50am
|
prodigy
Total Posts: 3029
|
Yes, normal maps are one of this wierd things.. :D
Time i ago, i found this (the most usesfull soft for normal maps creation)
http://crazybump.com/
Enjoy it! |
Post by rjeff // Mar 6, 2008, 3:14pm
|
rjeff
Total Posts: 1260
|
thanks prodigy..getting it now! |
|
