AutoCAD 3D Modeling: Spotlight
August 20, 2004
Spotlights are conical lights that can
simulate headlights of cars, shade lamps, and so on. Every
spotlight consists of two major angles called Hotspot and
Falloff. The Hotspot angle defines that portion of light
cross-section that retains a fix light intensity. The light
intensity drops to zero within the Falloff angle. The Falloff
angle is always greater than Hotspot. The spotlight can cast
shadow. You need to define a target point along with a location
point to define direction and location of the spotlight. The
following tutorial shows you a sample.
► I have used AutoCAD 2005 for this tutorial. However, you
may use another release of AutoCAD.
► User entries are in boldface.
8 symbol represents pressing Enter.
1. Download and
16_spotlight.dwg file. The file displays a shade lamp at
the corner of a room [Figure 1].
If you are using AutoCAD 2002 or an older version download
2. Render the
drawing (choose View > Render > Render). The rendered image
appears on screen [Figure 2].
3. Invoke the
LIGHT command (choose View > Render > Light). The Lights
dialog box appears [Figure 3].
4. From the
list next to the New button select Spotlight.
Click New. The New Spotlight dialog box appears [Figure
5. Type S
or another name in Light Name box. Highlight the
intensity value and type 100. Change the Hotspot and
Falloff values to 30 and 45 respectively. Select
the Shadow On check box [Figure 5].
Position area, click Modify. The dialog box
disappears. In command line enter target and location points as
Enter light target <current>: 0,0,0
Enter light location <current>: 0,0,125
7. Click OK in
both dialog boxes to close them.
8. Render the
scene again (choose View > Render > Render). The spotlight
effect appears [Figure 6].
9. Invoke the
LIGHT command once more (choose View > Render > Light). From the
list of lights click S – the spotlight name – and then click
Modify Spotlight dialog box under Shadows area clear
the Shadow On check box.
11. In both
dialog boxes click OK. Render the scene again (choose View >
Render > Render). The spotlight does not cast shadow anymore
12. Close the
file. Don’t save it.
About the Author
Alireza Parsai is the founder of
www.cadpanel.com. He is a
mechanical engineer with more than 13 years experience with
AutoCAD. Alireza is an Autodesk Authorized Author, the CAD
Director for HiTech Institute Canada, a contributing editor for
Augiworld magazine, a columnist writer for CAD Digest, and an
instructor for AUGI Training Program. He has written 8 books in
Farsi, 4 booklets in English, and more than 130 articles for
different magazines and newsletters. If you would like to attend
Alireza’s classes call +1 (416) 513 1535 or send an email to