One way to use patterns to paint gourds is to place a sheet of plastic wrap over the pattern, trace it onto the plastic, and then place the plastic onto the gourd on top of tracing paper. Another method is to make a stencil out of the pattern.
There are several difficulties involved with painting gourds, most of which arise from their unique shapes and often bumpy surfaces. While using a pattern to paint a flat surface simply involves placing it on the canvas area and making a copy, gourds require extra care to avoid unnecessarily distorting the pattern or missing out on sections completely. A common method for transferring the patter is to create a stencil out of a hard paper, such as poster board or thin cardboard. After making the stencil, use a pencil to trace out the basic elements of the pattern onto the gourd, and then paint over the markings.
One issue with this method is that you are unable to include some smaller details, depending on the pattern. To solve this, try using the plastic wrap method. Begin by placing a sheet of plastic wrap over the pattern and tracing it over with a marker. Place tracing paper on the gourd, and wrap the plastic wrap over that. This allows you to trace all the details directly onto the gourd.