Heights and models

Tips for creating and manipulating planet textures for Celestia.
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Art Blos M
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Heights and models

Post #1by Art Blos » 22.10.2017, 13:28

Hello everybody. I have a question.

Is it possible to use bump or normal maps simultaneously with a 3D-model? My attempts were unsuccessful. :sad:

I'll explain why this is necessary. It's about Haumea and her rings. When used parameter "SemiAxes", the rings become oval. When the model is used, the rings is round. But our model is smooth. We have fictitious maps of heights and would like to use them simultaneously.

Theoretically, it would be possible to make a model with the necessary dents from a bump map, but I think the main texture will not with them coincide properly (I found that it is superimposed on the model differently than on a simple ellipsoid).
Last edited by Art Blos on 22.10.2017, 14:38, edited 1 time in total.
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Post #2by john71 » 22.10.2017, 13:50

Bump or normal maps are two dimensional optical illusions, they are just virtual shadows and lights basically. 3D models are "real" objects in the virtual space, with "real" shadows...normal maps on 3D models are also illusions...specular maps are the the closest thing to a "real" normal map for a 3D object...

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Post #3by Art Blos » 22.10.2017, 13:56

john71 wrote:Bump or normal maps are two dimensional optical illusions, they are just virtual shadows and lights basically. 3D models are "real" objects in the virtual space, with "real" shadows...normal maps on 3D models are also illusions...specular maps are the the closest thing to a "real" normal map for a 3D object...
I understand the essence of the maps of heights. I am interested in the purely technical side of the matter. In the accessible documentation about the possibility of simultaneous use of heights and models nothing is written.
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Post #4by FarGetaNik » 22.10.2017, 15:55

Art Blos wrote:Is it possible to use bump or normal maps simultaneously with a 3D-model? My attempts were unsuccessful. :sad:

Yes it is possible to use a normal map on a cmod model in Celestia. Bump maps won't work. It is quite a difficult process, I discussed the matter on this topic: https://celestia.space/forum/viewtopic.php?f=30&t=17471

Art Blos wrote:When used parameter "SemiAxes", the rings become oval.
This gave me quite the laughs when I tried it :biggrin: maybe this should be something to be fixed in 1.7.

john71 wrote:specular maps are the the closest thing to a "real" normal map for a 3D object...
What have specular map to do with the matter? :eh: Illusion or not, normal maps give quite good results for objects that are relatively round, like planets and the larger dwarf planets.

If the normal map is purely fictional (maybe you are talking about Snowfalls'?) then the best way would be to use an ellipsoid model without topography and apply a normal map to it. The model needs to be a UV-mapped cmod.
Put it and the normal map in a folder where Celestia would expect it, so the mesh in a "models" folder and the normamap and texture in a "textures/medres" folder within the same parent directory. You have to open the cmod in cmodview, then do "Operations/Generate Tangents" and "Operations/Uniquify Vertices". Select the model, in the menue on the right you can now select the normal map and the surface texture. Make sure that all the textures you are using in conjunction (the regular texture map AND the normal map) are in png format, otherwise it won't work. Also the ssc file should not overwrite any textures, it has to be defined within the cmod materials.

Here is Ceres as an example:
ceres-normal.jpg

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Post #5by Art Blos » 22.10.2017, 16:14

FarGetaNik wrote:This gave me quite the laughs when I tried it
For me it's not at all fun. :cry:

FarGetaNik wrote:maybe this should be something to be fixed in 1.7.
Very much I doubt.

FarGetaNik wrote:If the normal map is purely fictional (maybe you are talking about Snowfalls'?) then the best way would be to use an ellipsoid model without topography and apply a normal map to it. The model needs to be a UV-mapped cmod.
Put it and the normal map in a folder where Celestia would expect it, so the mesh in a "models" folder and the normamap and texture in a "textures/medres" folder within the same parent directory. You have to open the cmod in cmodview, then do "Operations/Generate Tangents" and "Operations/Uniquify Vertices". Select the model, in the menue on the right you can now select the normal map and the surface texture. Make sure that all the textures you are using in conjunction (the regular texture map AND the normal map) are in png format, otherwise it won't work. Also the ssc file should not overwrite any textures, it has to be defined within the cmod materials.
Thanks, I'll try. :smile:
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Post #6by john71 » 22.10.2017, 20:47

Art Blos wrote:Is it possible to use bump or normal maps simultaneously with a 3D-model?

Use Anim8tor for basic UV mapping and after that cmodview (generate tangents). You may have to edit the ascii cmod file.

But in my opinion it is quite hard to match the normal map of a spherical object with the normal map of a much smaller 3D mesh.

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Post #7by John Van Vliet » 23.10.2017, 02:52

yes it is possible

have a look at this cmod
-- asteroid Bennu
https://drive.google.com/file/d/0B6ZYAd08tZL-S3NGYWRBaUNraTg/view?usp=sharing

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Post #8by CM1215 » 09.12.2017, 23:03

I have another question for you: Would it be possible to use a model, normal map, AND surface texture all at once?
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Post #9by John Van Vliet » 10.12.2017, 04:10

i used a lores height map( dem ) to make the mesh
then a hires bump map to make the hires normal map

Would it be possible to use a model, normal map, AND surface texture all at once?
that is a normal everyday cmod
Screenshot.jpg


i export a uv mapped mesh with the normal and texture in Blender to a obj mesh
open it in Cmodview

now there is a bit of a bug the textures need to be flipped vertically

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Post #10by CM1215 » 10.12.2017, 12:40

John Van Vliet, would it be possible to not use Blender, because I cannot find out how to use that program to UV map meshes...

I was looking for a method involving cmodview only. I already have the UV mapped mesh, just when I add the normal map and run it in Celestia, the normal map doesn't render (the model appears as if the normal map isn't there). I have no clue what I'm doing wrong...I made sure to use the operations "Generate Tangents" and "Uniquify Vertices".
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Post #11by CM1215 » 11.12.2017, 12:18

Why must I be ignored when I ask for a different solution?
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Post #12by selden » 11.12.2017, 12:56

It's impossible to guess what you might be doing "wrong" without having all the information. A typed description often can be misinterpreted or impossible to reproduce.

Among other things I'm probably not thinking of, you'll need to post the original model, the cmod version, all of the texture files you're trying to apply to it and the SSC you're using to try to display it.
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Post #13by CM1215 » 11.12.2017, 14:37

selden wrote:you'll need to post the original model, the cmod version, all of the texture files you're trying to apply to it and the SSC you're using to try to display it.
I can do that. Here I have posted all the files you will need to find out what is wrong. The iapetustest5.cmod is the model that has no normal map applied, and the iapetustest12.cmod is the model that already has the normal map applied, but won't render it in Celestia.
Here is the ZIP file:
IapetusModels.zip
(46.86 MiB) Downloaded 50 times
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Post #14by John Van Vliet » 12.12.2017, 00:27

there are so ,so,so,so,SO,SO,SO,SO many many many tutorials and guides and videos
YouTube alone has like over 5 thousand video guides on using blender

then there are all the step by step tutorials in video and pdf form

MAKE the coffee and doughnuts from the Step #1 Beginners TUTORIAL

a mostly spherical mesh is one of the easiest to do

BUT YOU HAVE TO RTFM AND RUN THROUGH THE INSTRUCTIONS


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