At this point in image to g-code process we know what lines to paint and what tool and paint color to paint them with. What we haven't accounted for are all the dynamics that come into play during the cnc painting process. How far can the brush paint on canvas before it needs to go back for more paint, how often does the brush need to cleaned so paint doesn't dry and build up on the bristles, what movement is required to load the brush with paint, how much paint is required to create the painting, is there enough room on the palette to fit all the paint needed to create the painting, etc. Solving these challenges requires more of a bookkeeping mindset than a mathematical one.

The first step of addressing these dynamics is to understand how much paint is required for each layer of the painting. Only three values are needed to arrive at the layer paint quantity estimate - the total distance the paint brush travels on the canvas during the layer, the maximum distance the paint brush can travel on the canvas before it needs to be loaded with more paint, and the quantity of paint required to load the brush. The latter two are determined through experimentation.  

The next step after determining how much paint is required is to map out where on palette to dispense the paint both so the paint management system knows where to dispense the paint and the six axis brush cnc machine knows where on the palette to go to load the brush with more paint. I have chosen the approach of dispensing beads of paint in rows that run the long dimension of the palette. If the length of bead that needs to be dispensed is longer than the length of the palette, the remaining bead length will be dispensed on the next bead row.

After the palette paint map is finished, writing the machine instruction g-code is just a matter of following the correct sequence of operations: 1) get the tool from its dock, 2) wet the brush, 3) load the brush with paint color 1, 4) paint on the canvas, 5) load the brush with paint paint color 1, ... 20) clean the brush, 21) load the brush with paint color 2, ... Each operation having unique movements and control parameters. Some that can be calculated and others that have to be determined experimentally. This is where the dimensional control parameters that I have described in a previous project log come into play.

Since many of the control parameters are experimental, the g-code writing script I developed writes all the relevant object control parameters at the appropriate location in the g-code file. I suppose as this project becomes more mature, these parameters may become standardized through experimentation and no longer need to be logged in the g-code file. Like I said; it's mostly bookkeeping. 

This concludes the bitmap image to paint stroke g-code project log series. I am always happy to answer questions or provide a higher level of detail upon request. Please post any questions and comments to the main project page.