Help With Window Reflection Controls

[Hauszeit]

Posted this in the Commons area before I realized there is a Sketchup specific group:

I’m new to Vray and I’m attempting to figure out glass reflections for exterior window glass. Vray 6 and Sketchup Pro 2022.

I’m trying to determine how to ghost the site reflection onto this model’s window surfaces so that the interior can show too. The completely obscuring reflection that I’m getting currently starts at a more obtuse reflection angle, so one window sash is see-through and next one further away is not. Both of the windows to the left have the same glass - they are both the same components.

I can see that people are creating graduated reflections determined by reflection angles, and on tutorials such as Justin Geis’s YouTube videos seem to make adjusting the amount of reflection simply a matter of changing the Reflection Color and it looks pretty simple, but I have tried all of the settings he uses to adjust reflections and none seem to have an effect on the sky reflection.

Does anyone know of a more basic tutorial out there? I’ve watched a bunch of videos over the last month, and I know I’ve seen glass reflections covered elsewhere, but I’ve failed to understand reflections and window transparency - I just need a step-by-step in-depth coverage tutorial.[

Coppola Sketchup Model Link](https://drive.google.com/drive/folders/1Mw8aS_ekVUyddx4j7MVMUO6G-V_UnbZh?usp=sharing)

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[natalia.gruzdova]

Hello @Hauszeit ,
Thank you for the scene.

I have made some changes to your material and here is the result I got. You can download the scene with changes here.

• Important thing to mention is that in your example the Refraction IOR was set to 1, which is the index of refraction for air, but not glass. You can search for the list of the Refraction IOR and Reflection IOR for different materials, and while it is not necessary to strictly follow it, it is good for starters.
• Also, I have unchecked the Thin-Walled option, you can read more about it here. Basically you would want to enable it for single-surface objects like curtains or leaves.
• And I have changed Reflection Glossiness to more glossy values (0.95) instead of the blurry ones you had (0.4).​

I encourage you to check available Glass materials in the Cosmos Browser to see how they are created and change them to get the result you need. For example Glass Window Neutral also works well in your case.

In the documentation you can find simple examples with sliders for almost every option:

• Generic Reflection
• Generic Refraction

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[Hauszeit]

Natalia,

Thanks for the tips on reflections and refraction settings for glass. I started with the Glass Window Neutral and randomly modified it while experimenting with the settings to get to what you saw in the model. Hopefully, I will be able to persist at V-ray long enough to know the basics of material qualities much more intuitively, and especially, when to leave things alone. So far, however, I found getting desired results a tough learn - V-ray is far less mechanical than other 3D programs that aren’t for photo realistic rendering, especially in the way a whole suite of variables must be coordinated to get to your desired results…

I tried to modify the glass in my model to match your settings, and the glass was not transparent if I toggled the Thin-Walled option off. I kept fiddling with things over the past week, and could not figure out what you had done differently from me when i was trying to match your material settings. I could copy your window into my model, and it would render to match your image, so I knew it was not some global setting that was causing the problem.​

Rendering with glass materials to match your settings is not transparent. The Region Render strip is with the glass material applied to the inside of the glass plane object.

I happened to come across a forum posting on translucency problemes, and someone mentioned applying material to both sides of a glass material plane. Sure enough, after applying the materials to the inside of my glass object (it has thickness/closed geometry - not sure what that’s called in Sketchup?), the material performed as it did with the model you uploaded. Did you also apply material to the insides of the glass?

One of my original concerns was over reflections and how the camera angle relative to the reflective surface affects its intensity. Only at a very acute angle do you start to get reflections in this model, but I do not know how to create reflections on two planes with differing orientations. If I knew how to control reflection intensity, I could create a different material for each side, but, so far, controlling reflections has proved allusive. Near objects and bright lights are the only thing that it is easy to control and many tutorials use these conditions in their examples.

I still have not found a good tutorial to help me to understand reflections better. The Chaos help pages, like the ones you’ve referred me to, are merely lists and definitions The examples images they show aren’t much better. They are also self-referential, so until you have a comprehensive understanding and learn the hermetic language of rendering concepts and functions, they are not of much use to a neophyte. Any suggestions for better tutorials, especially on my current issue?

Also, the Chaos video tutorials look great. They’re good for simple concepts and the general steps to setting up models for rendering, but they are simply too superficial with the their explanations for learning universal tricks for rendering. Worst of all, however, I have yet to download an associated model that was ready to render from where a particular video begins.​

[luisgamino2]

Hi hauszeit

There is no magic with vray, i have been using vray for so long more than 10 years.

This is major software in which you have to spend a lot of time to understand how it works.

I had been spending a lot of weekends using vray just to try some materials, some lights, some effects.

This is not photoshop, this is a complex software and you have to experiment again and again and again in order to understand how it works and then do your work.

telling you use this IOR, use this reflection vale, use the refraction vale is not right.

First you have to understand materials in real life and then aplied to your materials in vray.

I would you suggest watch Adan Martin tutorials in youtube, they are in spanish but you can activate subtitles

He is a máster with vray for 3d max and 3d collective is his web Page.

But vray for 3d max is kind of the same for vray for sketchup

so practice, and practice, and practice

Sometimes you would get mad, dont worry this is part to knowledge the software.

The tutorials from chaos group are in a very simplistic way they dont do a kind of complex tutorials because sometimes they dont have time

again dont worry, work and practice Hard in order to use vray at the highest level

I hope it helps!!!
Cheers!!!

[natalia.gruzdova]

Hello @Hauszeit ,
Thank you for your feedback. I will answer some of your questions below.
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Did you also apply material to the insides of the glass?
Yes, this seems to have been an issue as well after double-checking your original scene. Out of habit the first thing I did is that I applied material from the V-Ray Asset Editor (right-mouse click on the material > Apply to Selection). This way you can be sure that material was applied correctly to the whole object.
Sorry for missing that and I am glad you have pointed it out. Are you using SketchUp Paint Bucket mostly?​

V-ray is far less mechanical than other 3D programs that aren’t for photo realistic rendering
V-Ray strives to provide tools to achieve photo-realistic and physically correct results. Nevertheless, it does not mean you can not fake things to get the exact result you want. But as @luisgamino2 correctly commented, understanding how materials work in real life is useful. Still not only the reflections of the material itself is necessary but as you yourself noticed camera angle, surrounding objects and lighting have to be taken into consideration. This is why most examples try to create a setup that shows all that.
Lights
In your scene there is nothing for windows to reflect except for the background color. You can consider using an HDRI as the main light source for exterior renders, for example take a look at the options in the Light Gen. It will also allow you to determine what light angle is beneficial for your camera angle in terms of reflections.
Or you can Override only reflections in the Environment tab. This was also discussed in this forum post, perhaps you will find it useful too.

Render Elements and post-production
You can use Reflection and Specular render element to enhance these effects after the image is rendered, or add Back to Beauty render element that contains all main channels that may be needed for compositing.

I still have not found a good tutorial to help me to understand reflections better.

Regarding the tutorials perhaps these ones will be of help to you, even though V-Ray version it older one, but the workflow and techniques are well described:
How to create Real Vray Glass Material in Vray Next Sketch-Up Part 1
How to create Real Vray Glass Material in Vray Next Sketch-Up Part 2

I will share feedback with the dedicated team that such tutorials are wanted.

Additionally, you can always reach out to us on the forum or in ticket if there is something specific you are struggling with, and it would be most helpful if you could share some references of the renders you want to get, so we can assist you better.
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