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Casting shadows
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* December 25, 2009, 03:14:38 PM
I am trying to cast a shadow on a building I am designing to represent a shaded area, and was wondering if this can be done using the sky light tool and quality render. Any advise would be appreciated.

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* December 25, 2009, 04:05:26 PM
#1
I am trying to cast a shadow on a building I am designing to represent a shaded area, and was wondering if this can be done using the sky light tool and quality render. Any advise would be appreciated.

The Sky light acts like a whole bunch of individual light sources, and I've never been able to make it cast a nice shadow. Try the Directional light.

Henry H

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* December 27, 2009, 02:11:28 PM
#2
Would Shadow Catcher work?

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« Last Edit: December 28, 2009, 04:15:15 AM by wd »

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* December 27, 2009, 08:43:55 PM
#3
Henry, thanks for the reply. I tried both directional and spot lights without success. Is it possible to use Floor Plan to undertake this task?

You don't need Floor Plan, Bob. Both directional and spot lights will work in TCad. You need to aim the light(s) properly, and you need to render in Raytrace or Raytrace Full mode. And of course you need something on which to cast the shadow. Post the drawing if you can't make it work.

Henry H

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* December 28, 2009, 02:00:37 PM
#4
Henry, thanks for the offer to have a look at  the attached drawing. I will look forward to the results

Bob, open the View menu and click on "Lights." Then turn the Directional light ON ;-)
See attached screenshot. Only the Ambient light is currently on.

Nice drawing, BTW.

...Happy New Year!

Henry H

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« Last Edit: December 28, 2009, 02:22:03 PM by Henry Hubich »

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* December 28, 2009, 06:36:11 PM
#5
Henry, thanks for the reply, however I turned the directional light on, but still no shadows.

Shadows are there, Bob, but they look better if you correct the aim of the Directional light; you had it aimed straight down. To aim it, select it with the Edit tool and relocate the two blue nodes. Better to turn on at least the Headlight, too, in addition to the Ambient and Directional lights. Your drawing with the lights modified (renamed), and a screenshot of a rendering, are attached herewith.

Henry H

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* December 29, 2009, 05:54:28 PM
#6
Henry, just a quick question, is there a simply method in placing the directional light to get the correct direction

I generally place the light by starting in Plan view and the World Workplane, clicking the appropriate toolbutton (see attached screenshot), then clicking in the drawing one time to place the light itself, then clicking once again to establish the direction in which it points. BUT be aware that this "direction" is not yet fully defined, since it's really the projection of the direction in the current Workplane. To finish defining the direction, I switch to a Front or Side view, go to Workplane by View, select the light with the Edit tool (whereupon the light displays two small blue squares, one representing the light itself and the other its target), and relocate the "target" node as required. One more thing to be aware of is that the actual location of a Directional light has no bearing whatever upon how it illuminates things, since it behaves as if it were located at infinity; all that matters is the relative locations of its two blue nodes. And yes, it is awkward :-(

Henry H


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* December 30, 2009, 04:15:07 PM
#7
Henry, another issue I discovered when creating shadows, is that the material must must be changed to "matte" (in the materials editor) before shadows can be created. This may be of interest to other turbo-cad users.

You'll have better success using Luminance. The attached is an example.

don

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« Last Edit: December 30, 2009, 04:28:09 PM by Don C Wensrich »

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* December 30, 2009, 04:56:52 PM
#8
Hi Bob,

I don't think your 'matte' rule is true but I haven't tested it.

You should also make sure the intensity of the Directional light is 'strong enough' to outshine the Ambient light. You can set the power of the lights with Ambient lower than Directional, but you must also be aware that the colors also reduce or intensify a lights brightness.

In the attached I have Ambient set to .05 and Directional at 1.5. I then set the colors so Ambient was a dark 'gray' and the Directional  is white.

Lighting and rendering is very powerful in TCAD, take things a little at a time and it will add up to some great results.

Jack

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« Last Edit: December 30, 2009, 05:23:03 PM by Jack Zimmer »

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* December 30, 2009, 05:53:12 PM
#9
Henry, another issue I discovered when creating shadows, is that the material must must be changed to "matte" (in the materials editor) before shadows can be created. This may be of interest to other turbo-cad users.

Afraid that is not true, Bob.

Henry H

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December 31, 2009, 06:11:27 AM
#10
Hi Bob
I had a play with your file I hope you don't mind?
I like to use luminance were possible.
Have added a sun+eye light to your file.
click on the sphere go into properties, and adjust the luminance  intensity to the brightness you are after.
Have fun.

Nick

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* December 31, 2009, 11:03:03 AM
#11
Henry, maybe it is the way I have set up material properties, because when I was trying to cast shadows I had the ground material set to constant, but when I changed the material to matte  the shadows showed up, the same applied to surface brightness and shadow catcher, no shadows appeared. Thanks for your help in this matter.


Interesting that you picked the  Reflectance which does not display shadows. "Constant" does not accept shadows OR display any variation in surface brightness. Apply "Constant" Reflectance to a Sphere, for example, and it will look like a flat disk when rendered. A Box will look like a 2D polygon.

Henry H

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