Glass Window

n.jmurov

I'm trying to create a large glass window with some view behind it and I've got two questions.

1. I tried to apply the standard Glass shader preset, but it placed some sort of a sphere in the middle of my window which I clearly don't want. Is that shader intended for spherical objects? What can I use for a plane then?
2. I want to have sunlight stream through the window and am trying to use distant light for that but it doesn't work as the window is blocked by a plane with the view photo on it. What should I do?

Cheers.

Herald of Fire

1. Not sure what you mean by a 'standard glass shader' putting a sphere into your window. If it's doing that, chances are whatever shader you're using has a spherical mapping in the diffuse channel which isn't necessary anyway. I'm not sure there is such a thing as a 'standard glass', so it's likely something intended for another product. A picture of the problem, and a shot of the Surface Editor settings would help here.

2. Firstly, I'd get rid of the view window. If you want to use a background, let it render opacity and save it as a PNG. You can add a background in post using Photoshop or Gimp. This way you have more control, and don't have to worry about getting the lighting right.

If you're insistent on using the plane, set it to full ambient light (100%) so it's unaffected by the shade and set it to not cast shadows in the General settings in the Parameters tab.

n.jmurov

This is a shader called Caustic Glass, I found it in the shader presets folder. Since I never added any custom shaders, it must be standard.
See a screenshot below.

I'm not sure that I understand the second part of the recommendation. I can change the ambient to 100% which will allow me to light the view itself but to light the scene in the room, I need a distant light (at least I think so) and how can I make the light go through the view? as otherwise the room will remain in the dark?
OK, I could do it with post-work in this case (although I prefer it to be in the scene as I'm after a quick and dirty solution here), but what if I was making an animation, not a still picture? I don't know how to do it in that case.

Szark

To allow light through an object like your Background image plane is to turn off Cast Shadows which you will find in the Parameters Pane under Misc (I think, can't check as I don't have DS installed yet) but make sure you have the Plane selected first.

Herald of Fire

n.jmurov said:

This is a shader called Caustic Glass, I found it in the shader presets folder. Since I never added any custom shaders, it must be standard.
See a screenshot below.In this particular case, I'd say the lighting itself is the cause of the problem. The white 'sphere' seems more like glare from a light source. Double check your lights aren't getting in the way of the shot.

n.jmurov said:

I'm not sure that I understand the second part of the recommendation. I can change the ambient to 100% which will allow me to light the view itself but to light the scene in the room, I need a distant light (at least I think so) and how can I make the light go through the view? as otherwise the room will remain in the dark?

Ambient is a surface setting. It will make your background appear at full brightness regardless of what other lighting is in the area. This is necessary so other objects won't darken it. Essentially, it's like giving the surface its own light source.

Of course, this light source won't actually CAST light itself, so by disabling the shadows in the Parameters pane you can use your distant light to shine through the pane as if it wasn't there, which should solve your problem.

OK, I could do it with post-work in this case (although I prefer it to be in the scene as I'm after a quick and dirty solution here), but what if I was making an animation, not a still picture? I don't know how to do it in that case.Actually, for animation it's just as easy, since a good animator will be rendering to an image sequence before they commit it to AVI or MPEG. This means if there's any problems with a frame, you can just re-render one frame instead of all of them. Doing it this way also allows you to post-process each frame to give it a professional finish.

Richard Haseltine

The caustic glass is a Shader Mixer set-up for doing caustics, it isn't something you want to use on plain glass as it also requires special lights and cameras. To get glass, if there are objects behind that need to distort use refraction in a standard shader (this won't do much if you are hjust using a background image), and apply some reflection too while adjusting the specular settings (you want to turn Multiply through opacity off).

AndyS

Hi,

n.jmurov said:

This is a shader called Caustic Glass, I found it in the shader presets folder. Since I never added any custom shaders, it must be standard.

why do you apply a shader of what you don't know what it was designed for?

To create a glass window that behaves like normal is quite easy.

For a plane representing a window in a set I chose the following surface settings:

Diffuse:
choose a base color for the glass. I set it to RGB = 0, 64, 64 at 100% without any further texture.
Glossyness to round 70% or higher.

Specular:
some very light blue color at 50%.

Ambient to zero. (Glass should not glow in the dark) ;)

Opacity:
So every window is absorbing a little of the light, set the opacity to 5% or less.

Reflection:
It is my personal like. I sat the reflection strength to 20%.

To get the reflection, which is influenced by the opacity parameter, please don't forget to set the control "Multiply Through Opacity" to "Off".

For the "Lighting Model" I chose "Glossy (Plastic)".

So far that setting works fine fo my like.

You can try different variations of the parameters. I found that the render engine is handling the reflection not correctly. If you have a dark background behind the window, the reflection seems to be way too weak compred to our every-day-experience. If there is a lot of light in the background the render produces a still intense reflection in conflict to our every-day-experience.
But - HEY - DAZ is a free software. ...

n.jmurov

Many thanks for all your replies.

I've still got a few issues that I'd like to resolve.

1. Why am I getting these defects in my render now such as on Olympia's face and her hand?
2. On the previous screenshot, I was actually referring not to the bright white sphere to the left but the greyish light-reflecting sphere in the center. Here you can see it creeping into the image again (the yellow arrow).
3. The window frame is casting a shadow onto the image outside of the window, any way to fix that?
4. Overall, there still seems to be not enough light in the room even after I turned the light intensity to 200. It looks like the sun is really low in the sky, I think. What should I do to make it brighter so that it still looks like the sunlight is the only source of light?

p.s. ...and also, although I probably won't be needing it here as this will be just a short comic strip, how do I apply another image to a bunch of PNG files at once in post-processing? Surely it shouldn't be done manually?

StratDragon

it appears your discoloration (and artifacting) is caused by a shadow map in 3Delight.
Try and move the camera or the light slightly and see if it resolves.
If the discoloration persists use a ray-traced shadow for the light instead of shadow map.

The shadow can be turned off on the object in the properties pane. It's casting a shadow inside and outside the room, if you shut it off it wont cast a shadow either way, if you need it you must move the light thats causing the shadow to hit your back image plane, or move that plane back and enlarge it if necessary so it fills the image without being in direct line of the shadow.

AndyS

@n.jmurov

1. and 2. is because you're still using the water glass shader.
The different colors are the result of spectral scattering of the glass bottom.

3. This is not a shadow - it is the reflection of your back wall.
So this is correct.

4. Do you have any additional light in your scene? Normally you need some ambient light or corresponding substitutes (support lights to fill the room).

n.jmurov

Thanks guys, all good now.