gbLayout - MCM Edition

This page provides the latest online Help information for the MCM-specific featoures of gbLayout. Information on the basic operation of gbLayout is not covered on this page.

Return to top of document


Once a parts list has been entered, and a layout generated a user need only press the "3D" button on the top toolbar to see a 3D image of the layout. Then, to see the MCM just press the "MCM" button, which is one of 3 buttons provided to work with MCMs. Here's an image of just the 3 MCM buttons found on the lower toolbar (3D mode).

Pressing the "MCM" button will generate a 3D design, using the current 3D design properties.

Here is an image of gbLayout, with the 3D image of an MCM displayed.

Return to top of document

MCM Design Features

The image below show the basic design features of an MCM, including the terminology used throughout these Help pages.


gbLayout supports the following MCM design variations:


Return to top of document


There are 3 buttons on the gbLayout 3D toolbar which provide the MCM-specific features:

Here's a description of what each button does.

Return to top of document

Parts Library

The parts library used by gbLayout is simply a text file ("parts.txt"), with one line per part containing the following the following information. Separate part properties with a comma.


Here's a description of the properties for each part in the library.

To edit the parts library, click on the "Parts Library" label to open the file in Notepad. Make any changes/additions required and then save the file.

Lines which begin with an apostrophe are ignored.

You must restart gbLayout for the changes to be reflected in the Parts Library list of gbLayout.

Return to top of document


One the MCM is displayed, and anytime changes are made to its properties, the "Results" textbox will contain information about the information design, including the results of weight and thermal analysis of the MCM.

Return to top of document

Material Library

A default file called "materials.txt" is created by gbLayout. It contains a list of materials and their properites. The file may be edited by the user to add or remove parts.

The file contains one line per material. Each line contains a description, thermal density (W/C-in), and density (gm/in3). Separate each property with a comma.

Lines starting with an apostrophe are ignored.

Return to top of document

MCM Design Dialog

There are approximately 50 design properties a user may set to define the design of an MCM within gbLayout. All are set from the MCM Design Dialog, which can be displayed using the "Setup" button on the 3D toolbar.

The following diagram shows where the properites are used in the design of the MCM.

Here's a listing of all MCM properties:

Package Type

Package Outline

Package Elements




Perimeter Pads

Solder Balls

Thermal Model