You are here: Home > Support > Knowledge Base > Incorrect Light Distribution from Light Fixtures

Incorrect Light Distribution from Light Fixtures

Tuesday, March 5th, 2019

Problem: The light distribution from one of your light fixtures does not extend in the right direction relative to the block and/or does not originate from the correct point on the block.

Cause: There is an incongruity between your light fixture block and the IES file associated with it.

Typically, IES files extend in the direction of angle 0, which is the same direction most blocks face. If the file was not oriented correctly, the light distribution will extend at an odd angle from the block.

The origin of the light distribution is determined by the Design Master attribute CON_CENTER, or the insertion point if the attribute is not present. If the origin is not correct (for example, a block for a lamp mounted to a pole has its origin at the pole), the light distribution will not be correct.


Solution 1: Account for the differences in the Light Fixture Project Schedule. This solution allows you to change the light fixture for a given IES file in the current project without affecting the block definition.

Ribbon: DM Electrical->Devices-> dm_elec-ltgPS Light Fixture Project Schedule

Pulldown Menu: DM Electrical->Light Fixtures->Light Fixture Project Schedule

In this dialog box, the IES Rotation value rotates the light distribution. The Arm Length value moves the light distribution origin in the direction of the rotation angle.


Solution 2: Account for the differences by making changes to the block using the Open Block from Drawing command. This solution allows you to modify the block so it will always work with a particular IES file.

Ribbon: DME: Customization->Block Creation->Open Block from Drawing

Pulldown Menu: DM Electrical->Customization->Open Block from Drawing

Select the block you want to change.

If the direction is off, rotate the block to match the light distribution.

If the origin is off, move the CON_CENTER attribute to the correct location or, if the attribute is not present, move the block so the insertion point is centered on the correct location.

Save the block, then run the Redefine Block in this Drawing command and select the light fixture block.

Ribbon: DME: Customization->Block Creation->Redefine Block in this Drawing

Pulldown Menu: DM Electrical->Customization->Redefine Block in this Drawing

The block will update to reflect the changes. Continue making changes until the block and light distribution line up correctly.

Related Articles

Filter by
Post Page
Electrical Light Fixtures HVAC Diffusers Training Recording Electrical Training Circuiting
Sort by

Exempt Callout on Light Fixtures

Light fixtures marked as exempt are inserted on the drawing with an additional callout, which you may not want to display.


Exporting Light Fixtures or Diffusers for Reflected Ceiling Plan

Using the Copy Drawing and Remove Links to Database command, you can create a copy of the drawing that allows you to delete unnecessary entities without affecting the project.


Training Recording: Light Fixture, Receptacle, Equipment, and Switch Options

This training video teaches you how to customize light fixtures, receptacles, equipment connections, and switches using the Design Master Electrical Options menu.


Photometrics: Multiple Heads on a Fixture

Here are detailed instructions for creating light fixtures with multiple heads that will not cause your quantity counts to be wrong.


Three-Phase Lighting Circuits

2-phase light fixtures can be connected to a 3-phase circuit using the Circuiting command.


Training Recording: Electrical Mailbag November 2019

This training video teaches you how to troubleshoot certain point-by-point photometrics issues, model special use cases and distribution equipment, and more in Design Master Electrical for AutoCAD.



Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

System Requirements


Contact Support

Install & Update Instructions

Online Training

Knowledge Base

User Manuals


Release Notes


Wish List

Remote Support



Customer Stories





Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

Free Trial

Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

©2001-2021, Design Master Software, Inc