take the edge off CAD, Rendering

the Finished Result:

In this example, there is a Civil 3D Surface model with some large extruded rectangles to represent BORG like buildings with big shadows.

Stretch or Move the geometry -see the shadows update live

Change the time of day on the slider and the shadows adjust

What levers do we have to pull to make all this happen?

1. 3dconfig - Performance Tuning
2. Set up a Visual Style for shadows.
3. Specify Location and time - turn on the Sun.

Performance Tuning:

• Type 3dconfig - The Adaptive Degradation and Performance Tuning dialog opens
• Turn on ‘Full Shadows’>and set it to the top of the degredation order list
• Click the ‘Manual Tune’ button and turn ‘Full Shadow Display’ on

Create a Visual Style for Shadows:

• Click View > Visual Styles > Visual Styles Manager and make a copy of the ‘realistic’ style (right click, copy to clipboard and paste into same location).
• Right click the copy and select ‘Edit Name and Description’ - change name to ‘Shadows’
• Under Environment Settings, set the Shadow Display to ‘Full Shadows’
• Under Edge Settings, set Edge Mode to ‘None’
• Double Click this new style or drag it into model space to make it current.

Location and Time:

• Set the GeographicLocation: View>Redner>Light>Geographic Location. Pick from the list or enter Lats, Longs.
• Turn on the Sun:>Render>Light>Edit Sun Properties. Change Status to ‘On’ - Pick Date and Time.

Question 1: Do we have to worry about Coordinates/Units etc?

No! - it’s all good as long as you specify the location and time.

My understanding of all this (and I’m happy to be corrected) is:

• The sun is literally ~ 92 million miles from our planet.
• We can treat the suns rays as being parallel.
• The angle of incoming rays is calculated (from time and geographic location).
• As long as we’ve specified the nearest City (or Lat-Long), the software will calculate the correct angle and the coordinates/units will be irrelevant.

Question 2: Are the rays always parallel?

Yes!
- there is something about this crazy notion of the suns rays refracting in the ozone layer and branching out that makes us want to believe it, especially when you see a very cool photo like this.

Image courtesy of www.capetownskies.com

There is no truth behind the ozone refraction theory though - it’s all down to perspective. Imagine looking down the parallel rows in a vineyard, only on a vastly larger scale…

Question 3: Why would you use RDV?

• First of all, it’s funky and interactive.
• It takes the shadow/sunlight settings from Civil 3D automatically.
• It handles large ECW files being draped on to large surfaces with detailed options for shadows.

Is there more?

Yes there’s more, there’s always more. The topic will be expanded over time.

cheers,
SeanT