Celestia Forums

Hello!

Please, can anyone explain to me what is the normal map and bump map difference? One is faster than other? What?

Thanks.

A bump map attempts to specify relative elevation at each pixel. It's a kind of height-map. When viewed in an imaging program, they appear as greyscale terrain-style maps with white being "highest" and black being "lowest".

A normal map, on the other hand, represents the normal, or "up", direction at each pixel. The three color components (RGB) of each pixel are highjacked into storing the three directional componets (XYZ) of each normal vector. As such, a normal map appears a kind of purplish pink color when viewed as an image.

Bump maps cannot be used directly for rendering, because elevation information is not useful when doing lighting calculations. What's needed are the normals. So, when using a bump-map, it must be converted in software to a normal map before rendering. You gain some speed by doing this conversion before hand and just using the normal map to begin with.

I hope that clears things up.

- a b i o g e n e s i s -

And can I create a normal map from bump map. Maybe using photoshop?

Harpeum wrote:And can I create a normal map from bump map. Maybe using photoshop?

Exactly. nVidia provides a command-line utility and a photoshop plug-in that do just that. You can find them here:

Photoshop plug-in

Command-line utility

- a b i o g e n e s i s -

One other thing I should point out:

The method given above is the current "standard" method of generating normal maps. There are, however, some interesting, if unconventional, methods being investigated by certain other individuals on the forum.

These new methods involve keeping a much higher level of detail for as long as possible during the process and, as is obvious from the pictures, this produces much improved results. This method is discussed in detail in other threads.

I just thought I'd mention it here before Fridger did.

- a b i o g e n e s i s -

Harpeum wrote:
And can I create a normal map from bump map. Maybe using photoshop?

Exactly. nVidia provides a command-line utility and a photoshop plug-in that do just that.

as far as i know, you can't do a normalmap from a bumpmap in the photoshop. the programs needs 3 or 4 different channels(RGB, R, G, B). bumpmaps don't have 3 or 4, so you have to make the normalmaps from the surface maps. I think.

ElPelado wrote:as far as i know, you can't do a normalmap from a bumpmap in the photoshop. the programs needs 3 or 4 different channels(RGB, R, G, B). bumpmaps don't have 3 or 4, so you have to make the normalmaps from the surface maps. I think.

Making normal maps from surface textures is not going to provide the
desired results. Surface maps don't contain the needed height information. What you need to do is duplicate the greyscale "channel" a couple of times in Photoshop, converting an 8-bit greyscale image to a 24-bit greyscale image. Then the filter will work fine.

- a b i o g e n e s i s -

I know that i dont get the info, i tryed it.
so how do I do that(duplicate)?
I haven't thought abou that. good idea, thanks.

ElPelado wrote:

Harpeum wrote:
And can I create a normal map from bump map. Maybe using photoshop?

Exactly. nVidia provides a command-line utility and a photoshop plug-in that do just that.

as far as i know, you can't do a normalmap from a bumpmap in the photoshop. the programs needs 3 or 4 different channels(RGB, R, G, B). bumpmaps don't have 3 or 4, so you have to make the normalmaps from the surface maps. I think.

ElPelado:

You are just using Photoshop and the normalmap plugin incorrectly. If you load the grayscale bumpmap and click on the normalmap plugin, it must give you an error message! Since a normal map is a RGB file, you cannot do this starting from a graymap. So the remedy is most simple: Load the gray bumpmap and click in Mode on RGB which first and trivially converts the graymap to RGB standard. Then you proceed to the normal map plugin and everything will work fine...

Bye Fridger

ElPelado wrote:I know that i dont get the info, i tryed it.
so how do I do that(duplicate)?
I haven't thought abou that. good idea, thanks.

Unfortunately, my PC is going through some tough times at the moment and I am unable to run Photoshop. But, if I remember correctly, there is a panel that you can view called "Channels" or something like that. There is a button on that panel that will allow you to create a new channel. Do that twice and copy the bumpmap into each of the new channels. Select all of them and run the filter. That should work, I think.

You may also want to create an "Alpha" channel for the height information. The filter can either extract that data from the Alpha channel or use values specified in the dialog box. If you use the Alpha channel, you might need to reverse the colors in that channel to make it work correctly. I don't remember if this was a problem with an old version of Celestia or just an idiosyncracy of the plug-in itself.

- a b i o g e n e s i s -

abiogenesis wrote:Unfortunately, my PC is going through some tough times at the moment and I am unable to run Photoshop. But, if I remember correctly, there is a panel that you can view called "Channels" or something like that. There is a button on that panel that will allow you to create a new channel. Do that twice and copy the bumpmap into each of the new channels. Select all of them and run the filter. That should work, I think.

No need for all this. Just convert the grayscale to RGB and proceed.

You may also want to create an "Alpha" channel for the height information. The filter can either extract that data from the Alpha channel or use values specified in the dialog box. If you use the Alpha channel, you might need to reverse the colors in that channel to make it work correctly. I don't remember if this was a problem with an old version of Celestia or just an idiosyncracy of the plug-in itself.

- a b i o g e n e s i s -

Inverting the map is not needed anymore in recent celestia versions. That bug has been fortunately eliminated!

Bye Fridger

t00fri wrote:No need for all this. Just convert the grayscale to RGB and proceed.

Yes, of course! I had forgotten about that. Much simpler. Like I said, though, I can't use Photoshop at the moment so I was speaking from memory. Thanks for the assist, Fridger!

- a b i o g e n e s i s -

thank you both, I will try it soon and then make my own earth normal map

its fun making maps and i am learning a lot -all the time

I made two normalmaps using the photoshop like you explain me, but qhen I tryed them, the elevation looks very good, but I also see some strange small rectangles, here is an example of the normal that I made from the standart mars bump:


the same happened with a normal map for earth, made from a 4k bumpmap.


what can i do?

It looks like that normal map may have gone through a lossy compression method...and a horrible one at that.

so what can I do??

Nothing...when the file was compressed, the extra information was lost.

The only thing you can hope for is an uncompressed file for you to download.

Hi is your normalMap a .dds because that format dose have some artifacts
or was your oridginal a .jpg , and jpg's have BIG TIME artifacts