Object opacity issue

Started by Eugeny, August 01, 2020, 06:49:34 am

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Eugeny

Hello,

I seem to have a problem with object opacity.  

Here is a simple example that demonstrates the issue. I have an object (Obj reader). In it's surface shader I try to define an opacity value to make it semi-transparent. Now, in RTP preview the object looks as I expect. However, in a final render it shows either as completely opaque (for all the opacity values > 0.5), or doesn't show at all (for opacity < 0.5).

Am I doing something wrong here? Any help will be appreciated.

WAS

Unfortunately opacity doesn't handle semi-transparency the way you want. It's be cool to see am improvement here for various applications. 

What you can do is take a surface shader, and plug a glass shader into your main input, disabled reflections and make it double sided (I believe). Than you can plug your material into the child input, and your opacity mask into the mask slot. This will allow semi-transparency and works in some scenarios alright as a cheat.

Eugeny

Thanks a lot, your solution works.
Quote from: WAS on August 01, 2020, 07:46:14 amWhat you can do is take a surface shader, and plug a glass shader into your main input, disabled reflections and make it double sided (I believe). Than you can plug your material into the child input, and your opacity mask into the mask slot. This will allow semi-transparency and works in some scenarios alright as a cheat.

Thanks a lot, your solution works.

claudius

August 26, 2020, 03:42:03 pm #3 Last Edit: August 26, 2020, 04:16:05 pm by claudius
Quote from: WAS on August 01, 2020, 07:46:14 amUnfortunately opacity doesn't handle semi-transparency the way you want. It's be cool to see am improvement here for various applications.

What you can do is take a surface shader, and plug a glass shader into your main input, disabled reflections and make it double sided (I believe). Than you can plug your material into the child input, and your opacity mask into the mask slot. This will allow semi-transparency and works in some scenarios alright as a cheat.
Was, I had the same issue but I couldn't follow your instructions properly. Can you please describe those action a little more specificly? Just like I was a 4 yo kid... Plz!
The part I did not understand is "plug your material into te child input"

WAS

How about I provide a demonstration file so you can actually see what's going on.

This doesn't seem to work in TG 4.5.38 though. The whole result is semi-transparent, and solid areas aren't solid. @Matt ???

Matt

I am working on a fix now.

In the mean time you can use a Merge Shader to handle the mixing - that works.
Just because milk is white doesn't mean that clouds are made of milk.

claudius

August 27, 2020, 02:21:43 am #6 Last Edit: August 27, 2020, 02:38:27 am by claudius
Was, that was I got with your test file. Semitransparency is fine (all around that vortex, I mean). I have Terragen 4.4.67 trial version


Dune

It probably got changed in 4.5.38.

claudius

Ok, guys, now I had Was's job working (thank you sooooo much man, I owe you and Dune barrels of beer). I understand that to make an object semitransparent I do need to mask it according that procedure.
But how can I get a mask from an image map out of the object I have to make semi transparent?
In other words I have to make an airplane canopy. The canopy is a 3d object, not a flat one such as the card in Was's example. How can I mask that canopy?

I know, I know that this is a rookie question, but I did not find any tutorial nor explanation about it. 

Thank you guys!

claudius

Quote from: claudius on August 27, 2020, 04:05:12 amOk, guys, now I had Was's job working (thank you sooooo much man, I owe you and Dune barrels of beer). I understand that to make an object semitransparent I do need to mask it according that procedure.
But how can I get a mask from an image map out of the object I have to make semi transparent?
In other words I have to make an airplane canopy. The canopy is a 3d object, not a flat one such as the card in Was's example. How can I mask that canopy?

I know, I know that this is a rookie question, but I did not find any tutorial nor explanation about it.

Thank you guys!
Found it! Had to select "Object UV".... Ahem.... Ops.... :P Anyway now it works and I need only to refine everything!