DesignSpark PCB automatically adds openings in the solder mask for pads, however you may wish to add an opening for example under a power transistor tab to allow a copper area to act as a heatsink.
This can be achieved by customising the solder mask layer which allows openings to be added.
To be able to see and edit the solder mask layer please see "How do I add a solder mask"
We examine a simple three component PCB as shown below. The image has the silkscreen and Top copper enabled showing the through hole and surface mount pads.
Now turn off all layers and select the Solder Mask layer only for viewing and you will see the default openings in the solder mask, all other areas will be coated with the solder resist at manufacture. This is done automatically by DesignSpark PCB following your setting in the Design Technology. Should you require to modify these global settings, please see "How can I edit the mask aperture settings".
All of the above is done automatically, however should you require a custom opening in the solder mask, such as placing Q1 horizontally on the PCB and require direct contact with the top copper this is done as follows.
Using the tools select "Add a closed shape", Rectangle or Circle of the size and position required.
While selected use the shortcut key "L" and select the layer "Solder mask". Here we illustrate with a mounting hole for the component tab.
The shape is required to be filled, select the properties and tick the check box. Click "Apply" to update the PCB view.
You now have the opening in the solder mask as required.
Using the various tools from the toolbar the shape could be anything as required for your design.
NOTE. When you produce your plot files please ensure that "Pads-Only" is not selected or your "shapes" will not be included in the plots!
Producing the Gerber file for the layer and viewing in a Gerber viewer allows you to confirm the openings are as required.
To avoid confusion in the images no copper tracks or areas are placed, you will need to add the copper area acting as a heatsink to complete the design.
If you require to remove the solder mask covering a particular track path, this can also be achieved as described here.