Architectural glass questions

[cgarness]

I have had pretty good luck using the settings for basic architectural glass on the tutorials page. But with regard to the screenshot below I have two questions:



1. Why is the shadow from the sun in sketchup (left) different from the semi-rendered image (middle)? Notice the shadows at the base are not the same at all. I have unchecked the override options under both the GI and Background maps in the Environment tab and both are set to "default".

2. What settings do I need to change to the basic architectural glass to allow shadows to be cast inside the building (as it is on the sketchup model)?\

Thanks for any advice...

[dalomar_cg]

Re: Architectural glass questions

As for the first question, thats one for Joe as that should work for you.

With the second question there are a few things that could be happenning. The first thing is that inorder for glass to be rendered like glass it needs to be a solid, or more specificly an entrance and exit surface. With out the geometry being like this, then refraction never happens, and the material doesn't act like it should. If you do have a solid for your geometry then clicking affect shadows in the refraction layer of your material will allow those shadows to be visable inside. If you just have a single plane for your glass, then that requires a different material without refraction. Check the materials section and you will find a glass folder and a few materials in there (give me a few minutes though).

[cgarness]

Re: Architectural glass questions

The glazing is actually two single planes offset an inch from one another. Both of them are oriented towards the camera and both have the same glass material applied to them as described in the tutorial.

I’m not sure I understand how to make a “solid” material in SketchUp though. Its always just lines and planes, right? Can you explain what you are talking about?

I also notice that shadows do not fall on the glass itself. The extra-deep mullions extend 6” in front of the surface of the glass and should be casting some sort of shadow (similar to the way they do on the darker grey metal panels). Is this related to the shadows not showing up on the inside as well?

Thanks,
Gunnar

[dcauldwell_cg]

Re: Architectural glass questions

cgarness

As I use glass a lot, I had to experiment! Here is a quick set up using the 'architectural glass' suggested a few weeks ago (http://www.asgvis.com/index.php?opti...0&topic=2023.0) by dalomar, which I have found quite successful



As you can see, the mullions cast shadows on the glass, the sunlight penetrates the glass and casts shadows inside the 'building' - is that what you want?
However, it is only one (not two) panes of glass.
(much to my amazement it also seems to refract - but I've no idea why!)

The glass settings are



Regards

david

[cgarness]

Re: Architectural glass questions

Thanks David. I suspect having two panes of glass might be causing the problem. I will try removing one layer, verify my settings against yours, and see what happens.

However, I found two reasons why the shadows on the sketchup model do not match the shadows in the rendering:

1. It seems that V-ray does not respond to changes in the sun postion. I guess it locks into whatever sun angle that might have been active at some point? I am not really sure. But I do know that I have radically changed the sun position, updated my scene and saved the model numerous times yet still the sun still renders as if it is coming from a totally different direction what is being displayed in the Sketchup window..

2. I accidentally selected the entire building and the plot of land on which it sits (which is one component) and appled an aluminum matte material to it (you can see there is a lot of blue from the GI being reflected in the ground plane and some of the base stone walls). Yet I can’t seem to reverse this. I have tried selecting the component (or the groups of components contained within) and applying the material “none” to it to avail. It still maintains the aluminum material.

Ideas?

[cgarness]

Re: Architectural glass questions

Changing the component to "default" does get rid of the aluminum, but now everything is a medium grey instead of maintaining its default sketchup color.

Is there any way to revert to the default sketchup color as a rendering style?

[dcauldwell_cg]

Re: Architectural glass questions

cgarness

I've had the same problem - unable to get rid of a vray material once applied. I think re-applying another material (but not 'none') might work.

Re the sun location. Try setting the vray sun-light source back to 'default', then move the sun as you wish in sketchup, and then re-select vray 'over-ride sun parameters'. You should find that the sun has now moved.

David

[cgarness]

Re: Architectural glass questions

Thanks, David. I'll give that a try.

Gunnar

[Jorbu]

Re: Architectural glass questions

I've run into the same issues with the sun location not updating when rendering. My work around is to save my render options settings and then re-load them. That seems to remove whatever "lock" is happening with the sun location and and fixes the problem. If it happens again, I just reload my render settings if they didn't change and it works fine.

Joe, this sounds like a bug?

Jorge

[dalomar_cg]

Re: Architectural glass questions

The two separate planes are going to be an issue because they are not treated as a volume. To make a solid use the push pull tool on a single plane and extrude that the desired thickness of the glass. I don't think I got to upload everything that I wanted to before I left the office, so I will get to it when I get in tomorrow morning.

[joe_b]

Re: Architectural glass questions

I've run into the same issues with the sun location not updating when rendering. My work around is to save my render options settings and then re-load them. That seems to remove whatever "lock" is happening with the sun location and and fixes the problem. If it happens again, I just reload my render settings if they didn't change and it works fine.

Joe, this sounds like a bug?

Yeah it is a bug - check out this post and see if the workaround I post there helps out with the sun not showing up in the right spot. I thought I had fixed this issue - but apparently I didn't fix it in all cases.

[cgarness]

Re: Architectural glass questions

Does anybody know what setting will let these glass volumes receive shadows? (from roofs or overhangs)

Gunnar