Working with Composites

The following tutorials explain the most common tasks involved in working with composites:

• What is a composite?

• Importing a composite

• Creating a composite

• Viewing a composite

• Editing a composite

• Exporting a composite

What is a Composite?

A composite a single layer (and hence, a single Gerber file), which is made up of a set of positive (dark) and negative (clear) layers. They are used to route traces on power planes. In the example below, the first layer is dark, a second clear layer is used to create a path for the trace, and then a dark trace layer is used to make the connections. (For display purposes, the clear data element below is shown in black.)

By allowing the use of black and white for layer colors, VisualCAM allows accurate viewing of composite power and ground layers. Setting the negative layer to white and the positive layers to black will result in a very realistic depiction of the final film.

Tip: For accurate viewing and editing, it is important that the layers be placed in the proper order in the layer list. Also make sure the appropriate layer is active. In the above three-layer example, if the first dark layer is active, you will not see the other two composite layers.

The layers that are contained in composites may be edited as you would any other layers, using the standard VisualCAM Edit commands.

Because VisualCAM supports item-level polarity (items of different polarity can exist on a single, standard layer), creating composites is not necessary. However, as composites are still commonly used, the following tutorials explain how to work with them in VisualCAM. In many instances, both the Navigator and standard menu commands can be used to view and manipulate composites. Both methods are explained, so that you may choose whichever works best for you.

Warning: The standard 274-D format does not support composite layers or item-level polarity; to properly export a composite or layers that contain a combination of positive and negative data, you must use 274-X.

Importing a Composite

1. Select the File|Import|Import Wizard command.

2. In the first dialog box, select the directory that your composite file is in.

3. In the second dialog box, select the composite file you wish to import, and unselect any other files you do not wish to import. There is no need to load in an aperture list, as it is included in the 274-X file.

4. Click in the Data Format column. The Gerber Import Data Format dialog box appears.

5. By default, VisualCAM converts composites to single layers with item-level polarity. This allows for easier editing of the data. To maintain your data as a standard composite, select the Layer Composites option (under Assign 274-X Polarity To).

6. Click OK and complete the import process.

Creating a Composite

Creating a New Composite

If the layer you wish to add to the composite does not already exist, select the Setup|Layers command. Find a new, empty layer in the Layer Setup dialog box, and assign it a name and an appropriate layer type.

1. Select the Setup|Composites command. The Composite Setup dialog box appears.

2. The Composite List shows any currently loaded composites and the layers contained within them. Click the Create Composite button and a new composite with a system default name (such as "Composite 1") is created.

3. To add a layer to a composite, click and drag the desired layer from the Layer List to the Composite List. To remove a layer from a composite, drag the layer back to the layer list.

4. To change layer polarity, right-click on a layer within a composite to select a different polarity. A polarity of Dark means that the layer is to be displayed in the style a normal Gerber file is displayed. Clear tells VisualCAM to display the layer using the current background color. This has the effect of erasing, or "clearing", areas from an image that were previously drawn by a "dark" layer. Negative layers should be set to clear.

Using the Navigator to Create a Composite

If the layers you wish to add to the composite do not already exist, right-click on the Layers heading in the Navigator. A shortcut menu appears. Select the Add Layer command, and a dialog box prompts you to enter the new layer’s name. The new layer appears in the list. It is automatically given the type "Other" and its visibility is turned off.

1. In the Navigator, right-click on the Composites heading. A shortcut menu appears.

2. Select the Add Composites command. A new composite with a system-default name appears in the Composites list.

3. Click on a layer in the Layers list.

4. While still holding down your mouse button, move the cursor to the desired composite, and release the button (i.e. drag-and-drop the layer into the composite).

Note that if a layer already resides in a composite, it cannot also be added to another composite. To remove a layer from a composite, right-click on the desired layer, and a shortcut menu appears.  Select the Remove command, and the layer is removed from the composite. This does not delete the actual layer in the database—it just removes the layer from the composite. To delete layers, see the Layers area of the Navigator.

Converting a Set of Gerber 274-D Files into a Composite File

1. Select the File|Import|Import Wizard command to import the 274-D files.

2. Select the Setup|Composites command. The Composite Setup dialog box appears.

3. The Composite List shows any currently loaded composites and the layers contained within them. Click the Create Composite button and a new composite with a system default name (such as "Composite 1") is created.

4. To add a layer to a composite, click and drag the desired layer from the Layer List to the Composite List. To remove a layer from a composite, drag the layer back to the layer list.

5. To change layer polarity, right-click on a layer within a composite to select a different polarity. A polarity of Dark means that the layer is to be displayed in the style a normal Gerber file is displayed. Clear tells VisualCAM to display the layer using the current background color. This has the effect of erasing, or "clearing", areas from an image that were previously drawn by a "dark" layer. Negative layers should be set to clear.

Warning: If you choose to export your composite file in a Gerber Format, you must use 274-X.

Viewing a Composite

Composite layers may be displayed WYSIWYG by simply pressing the V hotkey. This nested command toggles composite viewing on/off. Composite viewing may also be controlled using the Setup|Composites command.

Using the Navigator to View a Composite

1. In the Navigator, right-click on the desired composite. A shortcut menu appears, a checkmark next to the Visible command indicates if the layers are visible.

2. If a checkmark does not appear, select the Visible command, and the layers in the composite are now visible in the workspace.

To hide the layers, select the Visible command again.

Editing a Composite

Deleting a Composite

1. Select the Setup|Composites command. The Composite Setup dialog box appears.

2. In the Composite List, select the composite you wish to delete.

3. Click the Delete Composite button. This command does NOT delete any data or remove any data layers. Only the association to other layers is removed. To delete layers, use the Setup|Layers command or the Navigator.

Using the Navigator to Delete a Composite

1. In the Navigator, right-click on the desired composite in the list. A shortcut menu appears.

2. Select the Remove command, and the composite is immediately deleted. This does not delete the actual layers in the database—just the composite information. To delete layers, see the Layers area of the Navigator.

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1. To delete an empty composite, click on the desired composite in the list.

2. Press the DEL key, and the empty composite is immediately deleted.

Tip: If you delete a composite layer set, the layers will remain tagged as "Composite". You will need to tag your layers with a new layer type.

Adding a Layer to a Composite

If the layer you wish to add to the composite does not already exist, select the Setup|Layers command. Find a new, empty layer in the Layer Setup dialog box, and assign it a name and an appropriate layer type.

1. Select the Setup|Composites command. The Composite Setup dialog box appears.

2. To add a layer to a composite, click and drag the desired layer from the Layer List to the Composite List. Note that if a layer already resides in a composite, it cannot also be added to another composite.

3. Click OK to close the dialog box.

Using the Navigator to Add a Layer to a Composite

If the layer you wish to add to the composite does not already exist, right-click on the Layers heading in the Navigator. A shortcut menu appears. Select the Add Layer command, and a dialog box prompts you to enter the new layer’s name. The new layer appears in the list. It is automatically given the type "Other" and its visibility is turned off.

1. In the Navigator, click on the desired layer in the Layers list.

2. While still holding down your mouse button, move the cursor to the desired composite, and release the button (i.e. drag-and-drop the layer into the composite).

Note that if a layer already resides in a composite, it cannot also be added to another composite.

Removing a Layer from a Composite

1. Select the Setup|Composites command. The Composite Setup dialog box appears.

2. The Composite List shows any currently loaded composites and the layers contained within them. To remove a layer from a composite, click and drag the layer from the Composite List to the Layer List.

3. Click OK to close the dialog box.

This does not delete the actual layer in the database—it just removes the layer from the composite. To delete layers, use the Setup|Layers command or the Navigator.

Using the Navigator to Remove a Layer from a Composite

1. In the Navigator, click on the plus box next to the desired composite. A list of layers in the composite appears.

2. Right-click on the desired layer, and a shortcut menu appears.

3. Select the Remove command, and the layer is removed from the composite. This does not delete the actual layer in the database—it just removes the layer from the composite. To delete layers, see the Layers area of the Navigator.

Converting (Flattening) a Composite to a Single Layer

• Select the Tools|Convert|Composite To Layer command. Select the source composite, and the empty destination layer in the dialog box, and click OK

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In the Navigator, right-click on the desired composite in the composite list, and select the Convert To Layer command from the shortcut menu. The composite is immediately converted, and is placed on the first available empty layer.

Exporting a Composite

1. Select the  File|Export|Gerber command.

2. While selecting the desired settings in the Export Gerber dialog box, click the Format button, and change the Dialect selection to 274-X.

Plotting a composite layer on a printer is equally simple. Just view your composite layers as described above and then use the File|Print command. The plotted image will appear on the page exactly as it does on the display.

Tip: Since the image for printing is created in a high resolution off screen bitmap, the film box and display grid may appear on the output page. You can disable this by setting the film box color to the background color using the Options|Configure command, and disabling the display of the grid using the G hotkey.