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Necrobotz
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Problem with transparency settings .obj file

Hi all!

I've created a model in Sketchup of a turntable that i have, it has the cover made of brown clear plastic.

Exported from SU to .dae, imported in SH3D, first time i've get this result in render on the 3Q :



I've get this refraction effect on the sides of cover, for this I used a RGB color value for cover. After a lot of tests changing values in MTL file (after export to .Obj from SH3D) I switch to a .PNG transparent brown texture.

Result:





After a lot more of tests with the .mtl file i'm unable to make the light passing through the cover and give a brown colored shadow on the surface of furniture (but maybe it's not possible), then i start thinking it's for .png texture, the render doesn't know what color it has!!, I must switch to RGB value again.

Result :



Again with the strange reflection on the faces of cover... but with the light brown shadow achieved more or less.

Editing again the mtl file with all possible combinations of parameters :

Illum from 1 to 10 : same result on all, strange refracction.

Ka, Kd, Ks set all to "0.627451 0.321569 0.176471" works with the shadow, but I think I do not quite understand what value changes each one of them sad

Ts: This value is not exported with SH3D and maybe it doesn't recognize it, but I did the test, I did not see visible change.

d: this value has no impact on transparency related to light, always gives a hard shadow, only the physical object is more or less visible, y think.

So i'm in trouble, can't find the correct values for what I want.

This is the real thing :



Obviously this is used and not as lustrous as I want to represent it.

The questions are :

01 .- I can use RGB values to give color to the cover and get a normal transparency on material?

02 .- Is it possible to get colored shadow with the use of a transparent png texture?

03 .- When in SH3D I import the exported .obj file, change values of shininess of materials, export and import again they are lost, what is in the mtl file the value for this to change by hand prior to import in SH3D?

04 .- What mtl file values does SH3D recognize?
I have been reading in wikipedia many that I am not sure will be recognized or applicable.

05 .- Anyone knows a site when explain in Spanish the MTL file values clearly that I understand it well?

This is the last result I achieved with the values I put below



newmtl TapaPlastico
illum 2
Ka 0.627451 0.321569 0.176471
Kd 0.627451 0.321569 0.176471
Ks 0.627451 0.321569 0.176471
Ns 1.0
Tf 0.627451 0.321569 0.176471
Ni 10.0
d 0.9
map_Kd Dual1214V2_TapaPlastico.png


If anyone wants the file, it is available here:

Link

PD. I made a first version with double lid walls, with the normals pointing inside of themselves, to get a visibility effect of the back wall through the front one, but it did not work either well.
[Aug 21, 2017 1:23:55 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Necrobotz
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Re: Problem with transparency settings .obj file

No luck?
[Aug 26, 2017 10:32:10 AM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
dorin
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Re: Problem with transparency settings .obj file

I've try this:
newmtl TapaPlastico
illum 1
Ka 0.627451 0.321569 0.176471
Kd 0.627451 0.321569 0.176471
Ks 0.627451 0.321569 0.176471
Ns 1.0
Tf 0.627451 0.321569 0.176471
Ni 10.0
d 0.7

without the "map_Kd Dual1214V2_TapaPlastico.png".
Is not need wile this is a transparent material.
You could try different value for d (transparency).
or this
newmtl TapaPlastico
illum 1
Ka 0.2 0.2 0.2
Kd 0.5 0.7 0.8
Ks 0.0 0.0 0.0
Ns 1.0
d 0.4

Hope it help!
----------------------------------------
A computer program does what you tell it to do, not what you want it to do. Murphy's Law (Greer's Third Law)
If all else fails, get the instructions back out of the rubbish bin and read them. (bluewater - the aptosid manual maintainer)
[Aug 26, 2017 10:37:41 PM] Show Printable Version of Post    View Member Profile    Send Private Message    Hidden to Guest [Link] Report threatening or abusive post: please login first  Go to top 
Necrobotz
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Re: Problem with transparency settings .obj file

Thanks a lot Dorin!

I try this tomorrow!

Still confused with the Ka, Kd, Ks, Ns, Ni.... parameters, don't find a clear explanation about this without enter in a nightmare of terms and different webs...

Tomorrow I try and tell.

Sorry for my english.

Thanks again!
[Aug 26, 2017 11:37:22 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
dorin
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Re: Problem with transparency settings .obj file

My English is also bad, but in computer I prefer'it.
1.I'm a amatory in 3D.
2.The best documentation I've found:
wikipedia
and
mtl file
3.The Ns and Ni is not so important for the start. You must make many test until You have a acceptable result.
4.I suggest to remove some texture from furniture:
-edge
-material (gren color)
5. Try also modify this:
illum 9
d 0.7
Good luck!
----------------------------------------
A computer program does what you tell it to do, not what you want it to do. Murphy's Law (Greer's Third Law)
If all else fails, get the instructions back out of the rubbish bin and read them. (bluewater - the aptosid manual maintainer)
[Aug 27, 2017 9:39:09 AM] Show Printable Version of Post    View Member Profile    Send Private Message    Hidden to Guest [Link] Report threatening or abusive post: please login first  Go to top 
Necrobotz
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Re: Problem with transparency settings .obj file

Hi Dorin!

Finally i have time to try this, the first MTL gives high reflection, near a mirror thing, but the second works ok!!!
Thanks a lot!!

With experiments I've concluded that the refraction parameter is "NI", with a very bright 10.0 value for the material, but with 1.0 is perfect, the exact brightness.

Strangely it can not reproduce the internal reflex effect that happened before ....

The shadow of brown light has not yet been obtained with the two top qualities of rendering.

As I read the parameter that is responsible for this is "TF" (transmission filter), but it may be that SH3D does not recognize or simply does not make use of that parameter.

As I am very stubborn, I will continue doing tests until I get it, if it is possible ... for more that I have searched I can not find in the forum or the SH3D website what parameters on MTL files are supported by the program or how these are interpreted.

I have to investigate more about this, I know the DAE files are in principle more advanced and modern, but they are also from my point of view much more chaotic, the facility to simply modify the MTL file obviating the rest of the geometry of the OBJ file is much More comfortable and clean.
Besides that almost all the information on these subjects is in English with a quite technical language sometimes, which as you will see is not my native language, this lack of information in Spanish is also another barrier.

Well, thank you very much again, it has been a great help Dorin! ;)
[Aug 31, 2017 9:28:37 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Necrobotz
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Re: Problem with transparency settings .obj file

Sorry, I had not read your second answer, I had not updated the page until I answered.

LOL! The pages that you indicate to me are exactly the ones that guided me! But I get lost with the properties of specular, diffuse, environment ... I end up with a lot of other webs open looking for meanings and in the end I do not know what I was reading ...

The textures and materials that I do not use automatically delete them when I export from SH3D as you say.

My working method is:

I make the model in SketchUp.
I export as AED.
I import the DAE into SH3D.
I modify some values ​​to fit it as it is represented in SH3D.
I export as OBJ from SH3D.
And finally I import the obj again.

The question is that in the last export / import some parameters are lost as the brightness of the materials, I do not know if it will be some internal parameter of SH3D (the slider in the material editor).

This world has a lot to learn, but it's also a lot of fun.

I just saw that you are Romanian! Your English is better than mine!

Multumesc Dorin!
[Aug 31, 2017 9:49:38 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Necrobotz
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Re: Problem with transparency settings .obj file

Ok!!! Finally I have the solution!!!
After lot of tries and lot of mistakes, I found the reason of the reflection in the render, it is because the normals in the lid of the model, that have the transparency, it need another face inwards pointing to the inside of the model, if it is not present it gives the strange refraction effect, I mean it needs to have volume, not only a simple face.
Then it gives the wanted effect, it have normal transparency and gives a light brown coloured shadow.



It must be a beginer mistake but i'm very happy to found a solution for this problem that gives me headhache for days....

Dorin, until now i don't know how you did to bypass the refraction effect in the model with only one face in the lid, you`re good!! ;) Thanks!!
[Sep 3, 2017 8:50:58 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
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