My first Interior Scene

[Tegi]

Hi All
Yes, this standard room, filled with a few details from the 3D Warehouse, surely is not a big thing. But since I like the result, I like to post it here and ask you a few questions about such a scene and I am happy about any tip...
One task was to illuminate the room only with sun light that shines through the window. For that I have placed an emitter material (Sky Portal, Invisible) outside the window. - I'm not sure if I have to place such a material to allow daylight flowing into the room? It would be great, if someone here could give me any information on this issue.
The floor lamp at the chair appears as a light but I've just used a fake emitter material. A "fake emitter" is not a light source - I hope that I have understood that correctly?
For render settings I used "09. Interior (Progressive Render)", for the environmental lighting I used a standard Physical Sky setting

With a resolution of 3020 x 1200 px and 31 passes, this rendering took 12 hours which is pretty long for such a little scene setting. I am really happy with the render and lighting quality, but maybe there is a way which is slightly faster?

[Fletch]

Easy 08, 09, 10 render settings do not allow "fake emit" materials, they are rendered as emitting light.

For info using Sky Portal, see the tutorials in this thread:
Subject: Sky Portal Material Library for Twilight Render

That said, I would avoid sky portal, and just place an invisible light emitting rectangle or spot light right outside of the window to flood the room with light. Leave physical sky as default, or add a spherical sky image, but leave the default sun settings.

Increase exposure of the image in the Render Window.

See example:
Subject: Render Challenge No1 for Twilight V2

See also:
Subject: Interior Renderings - Exposure for Background Outside

Please read the FAQ (Frequently Asked Questions) starting out you will learn a lot here,
your question is possibly the most commonly asked question. Subject: Light through a window...

Subject: Breakfast Room

Happy New Year

You too!

1. Use only ONE pane of glass: Are you saying only one surface in SU or a box representing the thickness of a pane of glass? I actually have been using a solid box for glass that is the thickness of an insulated glass unit, so it fits the sash. Therefore it is about 3/4" thick.

one pane means precisely that...one single face... insulated glass units are either 2 or 3 panes of glass. This will also render ok, but means more reflections and potential for longer renderings or rendering artifacts (calculation errors)

2. I'm never sure what I am doing with back faces and glass texture in SU. Somehow I get it to work.

If it's not broken, don't fix it.
In SU, the white face is the front... the blue face is the back. So, try to always paint the white face. If the back face is painted, but the front is not, then the back face's texture will render fine. But if you paint a back face, then put that face into a group (like a window, for instance) and then you paint the entire group or component with a material texture or color then that color will render on the front face of that object, the color you painted onto the back face in this case will be ignored.

3. For a Sky Portal, would you

I would avoid sky portals.
Subject: Applying materials

Hi John, Nickchun is correct, but I want to discuss sky portal.

Sky portal is for a very specific case - only for use with interiors rendered with Easy 09 or Easy 10. If this is not the case, it is suggested not to use it.

If you are rendering with Easy 09 or Easy 10, the point of using Sky Portal is that it is supposed to, theoretically, cause all the photons from sun and sky to enter into the space through the portal. The purpose of doing this is, theoretically, the image will receive more light photons and resolve/clear more quickly.

After some pretty serious experimentation with different scenes on my part, and others, I've come to the conclusion that sky portal may work. But there are better options for achieving the same goal. These are the same options used in many other render engines...

1 - set spot light or spot lights outside of the space and focused on the windows matching the angle from the sun. adjust radius and color of the spot lights to taste for soft shadow and color of light.

2 - apply light emitter and set it to "invisible" in the template material properties for the emitter material. Apply this light emitter to a plane that fills the window, and just outside the glass a few centimeters/inches.

either of these will much more effectively provide more light coming into the space, and cause the image to render more quickly on Easy 09 or Easy 10 render settings.

4. In one technique you recommend using Physical Sky. Doesn't a Spherical sky image provide more realistic reflections etc-- or is that generally superfluous i an interior?

Physical sky is recommended because it gives most reliable / predictable lighting results. If you are a bit more experienced, and desire the reflections or to see a background image, then spherical sky is obviously the way to go. If you experience over-saturated color in your rendering from the spherical sky image, open the image in an image editor and desaturate the background image by 10-15% and save, then reload it into the sky and re-render.

5. Elsewhere you mention lower the resolution on an hdr to speed rendering. Do you know of a software besides PS or other expensive one that can open these and modify on a Mac?

Google will be your friend here.
Does HDRshop work on Mac?

[Tegi]

thank you Fletch for these many hints!
to become familiar with the more proper procedures, I will work through these notes and report here