topic Re: Reverse light in Visualization

Reverse light

Anonymous — Thu, 11 May 2023 12:39:52 GMT

Hi mates,
I was searching the documenation and also this awesome board but couldn't find a solution for this:

I want to design shining floor in a bathroom.
I need a reverse light tool but can't find any - nor any kind of parameter.
I mean I need a light that will shine from down - up, from floor to ceiling

There is a lightning PANEL but only with traditional light.
Please help me,
regards
Mar

Re: Reverse light

Andy Thomson — Sun, 03 Dec 2006 22:37:50 GMT

These ones aren't doin' it for ya?

Re: Reverse light

Anonymous — Sun, 03 Dec 2006 22:51:48 GMT

Of course not.
I want to be able to make a shining bar for example.

Re: Reverse light

Andy Thomson — Sun, 03 Dec 2006 23:00:57 GMT

Have you tried messing with materials? In 'reality' where is the light coming from? A valence? Translucent tiles? Or is the room just too dark?

Re: Reverse light

Anonymous — Sun, 03 Dec 2006 23:57:37 GMT

andyro wrote:
Have you tried messing with materials? In 'reality' where is the light coming from? A valence? Translucent tiles? Or is the room just too dark?

1 My bathroom doesnt have natural light
2 I want to make a source of this light --> lets say it can be a shinning bar which I want to place in the floor.

As I said before I need to make a light which source will be installed in the floor but it will shine in oposite direction

Re: Reverse light

Anonymous — Mon, 04 Dec 2006 00:27:58 GMT

Search for advice by Dwight, from his book, describing either a plasma tv screen or neon / fluorescent lighting. This should point you in the right direction. Or just buy his book.

The trick is that the object does not provide the light source itself, it is a prop, and the light source is actually from the objects andyro mentions.

Re: Reverse light

Andy Thomson — Mon, 04 Dec 2006 02:28:56 GMT

Using the settings in that material screnshot to make light strips in the floor, and setting an uplight with parallel sides (cone shape = cylinder) and making the object larger than the room - you get the effect s2uart refers to....

Anyways, you can plop those in valences or do the Billy Jean floor, whatever works...

Re: Reverse light

Anonymous — Mon, 04 Dec 2006 02:39:32 GMT

You could try opening "strip lamp" and "saving it as" under a different name
then go into the 3D scipt and right at the top type mulz -1 and then
save the part. This creates a rectangular lamp that points upward.
Peter Devlin

Re: Reverse light

Andy Thomson — Mon, 04 Dec 2006 02:51:46 GMT

Great idea Peter, the object becomes stretchy, but the light is still cast from a square (with a silly cone) in the center....see screenshot below...is there perhaps a way to modify the uplight cone to be truly a parallel light object, then we could use the tilt angle parameter to direct it. Even if inner and outer cones are set to zero degrees, the object still casts raking cone light....which is why I typically make thes objects huge, but then the effect is not entirely accurate...

What to try next??

Re: Reverse light

Anonymous — Mon, 04 Dec 2006 03:14:14 GMT

Andy,
I know very little about lamps because I rarely do interior renderings.
Looking at the code for a light source type object in the GDL manual,
I can see that GS does not have a truly diffuse light source
so apparently we are stuck with some form of cone shape.
I have never created a light source type object so I don't
know if what you are asking is possible in GDL.
Perhaps someone with experience coding light sources
could answer your question.
Peter Devlin

Re: Reverse light

Andy Thomson — Mon, 04 Dec 2006 03:30:49 GMT

a cone is fine, just a cone with 89.999 degree walls would be nice!

Re: Reverse light

Anonymous — Mon, 04 Dec 2006 04:07:09 GMT

Andy,
Looking at the parameter list of the object "strip lamp 10",
I notice that some of the parameters are hidden.
If you un-hide them you might be able to get the
control you are talking about.

Again looking at the code for the LIGHT command
it appears that one can make a cylindrical light source
if the radius is set to the cylinder radius you want and
the two angles, one of which is hidden in this object,
are set to zero.
Peter Devlin

Re: Reverse light

Dwight — Mon, 04 Dec 2006 04:09:34 GMT

Peter wrote:
code for a light source type object in the GDL
GS does not have a truly diffuse light source
so apparently we are stuck with some form of cone shape.
Peter Devlin

Partly true, partly not.

My book spends a lot of time demonstrating making and controlling diffuse light using the light cone light source. Exercises in the book indicate precisely how to illuminate an entire room with soft light coming from only one light source. This information remains current from Archicad 9 to Archicad 10.

The "light cone down" is the energy source used by most of the "lamps" along with the magical "wall light diffuse."

In doing the travelling seminars, I've been expanding this part of the lecture to make upp for simplifications in sunlighting techniques available in Archicad 10. The seminar is coming to the Bay area, Los Angeles and Orange County at the end of January.

Buying the book will immediately give you the power to cammand this light, or you could experiment for a week on your own like I did.

The attached image is one of the light cone development exercises I did in discovering how to control soft llighting.

Re: Reverse light

Dwight — Mon, 04 Dec 2006 04:12:17 GMT

Furthermore, an entire room can be illuminated by just one light source.

Things work better if you use a little fill light. In this example, there's a golden "general lilght" to the left of the camera.

Re: Reverse light

Dwight — Mon, 04 Dec 2006 04:18:23 GMT

The wall light indirect actually has a "Diffuse" setting, but it is hidden at the bottom of a long list of parameters. This is overly modest and certainly is a quality posessed by the sister of the girl you are dating but don't find out about it until after the engagement.

I think Graphisoft really messed up naming this light source and by placing the diffuse control at the bottom. Joke on us. Haha.

The attached image shows a naked wall light indirect with "Show light cone" "ON." This exposes the vertical cone that is normally even more diffuse. You'll find this source in wall lamps.

Re: Reverse light

Dwight — Mon, 04 Dec 2006 04:27:02 GMT

And the last thing I am giving away tonite in a vain attempt to clear the last copies of my book prior to Christmas is the way to fool the eye into thinking you have a light emitting surface when you don't. And that is by making your strip lights have a "Constant" reflectance shader and for wacky extra colors, an attenuated emission shader. This is how we make thousands of light fixtures in a building without incurring a useless rendering time hit.

For instance, the attached has no interior lights.

Some of the lads have alluded to things in the book that solve this problem, particularly not expecting the lamp to be the light source. Keep them separate.

Re: Reverse light

Dwight — Mon, 04 Dec 2006 04:36:25 GMT

Okay, one more, but it is a promo for my upcoming California Seminars. Further to the llight cone issue, there's several ways to illuminate large interior spaces with a mere hanful of lights. Here's a test room with just three lights.

Re: Reverse light

Anonymous — Mon, 04 Dec 2006 04:37:52 GMT

Hello Dwight,
I guess what I meant by the term "diffuse light source" would be
a light source that is like a radiant panel or like a giant CRT screen
that covers an entire wall or an entire floor.
The effect of such a lighting device on walls, ceilings, and objects
would be that there would be no fall off edges, no matter how diffuse,
and there would be no shadows in corners.
Are we using this term in the same sense or differently ?
Thanks,
Peter Devlin

Re: Reverse light

Dwight — Mon, 04 Dec 2006 04:53:04 GMT

That would be your windolite.

Or overlapping light cones that extend past the walls.

All of these need to be modulated with a general light source, but it is free in the rendering time because it casts no shadows.

Re: Reverse light

Anonymous — Mon, 04 Dec 2006 05:07:18 GMT

Hello Dwight,
When you say "That would be your windolite. "
are you referring to the "window light" object in the lightworks folder ?
Thanks,
Peter Devlin