Having troubles with transparency

[Fox]

Hey guys,

first of all I want to say that I'm still a newbie when it comes to 3D rendering. Today I installed trial version of Indigo (using Google Sketchup 7.1) and so far I understand pretty much all of the main functions but I came across with a problem: I've been trying to render a room that has glass walls, those walls should be transparent (keeping the blue colour of the glass but still being enough transparent to see objects on the oposite side of the walls.
I tried everything: In the material editor I tried to edit reflections, roughness, transparency checkbox etc and I just cannot make it transparent. I get either solid blue object or solid black.

Can anyone give me a hint what should I do?

Thanks and best regards,


Fox

[StompinTom]

Since Indigo models its materials on the physical world, your glass walls need thickness. Otherwise, the whole interior of the walls is taken to be glass, which means that all light will be absorbed by the time it gets to the other side, which means a black or blue image. You have to model panes of glass with their respective thickness.

[dag]

Here's the simplest blue glass you can get.
Save as igm file and open in mat editor. Change absorption coefficient spectrum to adjust color.
0 0 0,8 = max blueness
0,7 0,7 0,8 = no blueness very much for you

Code: Select all

<?xml version="1.0" encoding="utf-8"?>
<scenedata>
	<medium>
		<name>blue_glass_medium</name>
		<precedence>2</precedence>
		<basic>
			<ior>1.5</ior>
			<cauchy_b_coeff>0</cauchy_b_coeff>
			<absorption_coefficient_spectrum>
				<rgb>
					<rgb>
						41.6496 41.6496 10.1429
					</rgb>
					<gamma>1</gamma>
				</rgb>
			</absorption_coefficient_spectrum>
		</basic>
	</medium>
	<material>
		<name>blue_glass</name>
		<specular>
			<internal_medium_name>blue_glass_medium</internal_medium_name>
			<transparent>true</transparent>
			<layer>0</layer>
		</specular>
	</material>

</scenedata>

Off topic: Tried adding the igm and got "The upload was rejected because the uploaded file was identified as a possible attack vector."

[Pibuz]

Hi Fox.
Please post your test render so we can identify your specific issue.

Yet, I can assume you're doing at least one of the following things:
1. your SU mat is set uncorrectly: change the SU glass mat color to a much lighter tone and decrease the opacity slider to something like 10;
2. Your glass is modeled as surface but you applied a specular shader: switch to Thin Glass;
3. Your glass is modeled as volume: check your normals, they must be pointing outwards.

[Fox]

Hey guys, thank you for your replies;
Yesterday I somehow managed to make the glass walls transparent when I found the option "Thin Glass" as Pibuz mentioned. That did the trick but I need to adjust something to make the glass tinted blue as now is simply transparent as any other standard type of glass.
Also I would like to reduce the transparency just a little bit making the glass walls at least 10% more blurish (not to be as clean as it is now....I could use it for "Ajax windows & surfaces" commercial now lol).
I'm truly sorry for not being able to upload the picture since I left it at work but I'll do it in couple of days.

@ Dag and StompinTom; you are right on the glass thickness, I'll make them more thick since my glass walls are now paper-thick.

Once again gents, thank you very much for your quick feedback on this matter.

Have a pleasant weekend.

Cheers, Fox

[Pibuz]

Note that Thin Glass can be applied to volumes, but Specular glass cannot. So if you applied TG you obviously got transparency, but you gave up colorizations.

To make sure you can adjust some advanced glass settings, be sure to model VOLUMES (boxes) and apply a specular shader; give it SLIGHT opacities to get tinted glass. If you want to get not-perfectly-transparent glass you may want to use a Glossy transparent shader, that is basically a specular shader in which you can define the exponent value. Use low values (like 10, 50,..) to have rough glasses, high values (5000, 8000 will do the job) to get less blurry window panes. Remember that 1.000.000 gives perfect lucidity.

[Fox]

To make sure you can adjust some advanced glass settings, be sure to model VOLUMES (boxes) and apply a specular shader; give it SLIGHT opacities to get tinted glass.

I know it might sound stupid for a professional like yourself but I have to ask you this; where can I change or select this option to use/work with VOLUMES?

Once again thanks a lot on your kind assistance.

Regards,

Fox

[Pibuz]

You don't change it.
Simply, if a specular mat isn't applied to an enclosed volume, it will work strangely, as in your case.

Volumes are identified as "enclosed" if there is no gap between the faces that make up the solid.
In most cases you want volumes for windows and doors, so my suggestion is to make boxes separately and then to transform them in groups or components.

[Fox]

I think I understand what you are refering to; I'll try to put your advices into practice after the weekend. Currently I'm in test phase whether to use Indigo in profession (working as a development technologist at the airport development department and using it right now on designing new part of the terminal building) but so far it looks like I'll be ordering it next week .

Regards,

Fox

[Zom-B]

Interesting area you work in. I hope we can see some of your progress here in the WIP area.
We exchange knowledge and tips & tricks for pictures of your work