Previously in the Design Gene series we introduced how an organism is grown from the design genes themselves (see Part 3). 

Here we will take a deeper look at how the the phenotype evolves from the genotype, i.e. how a viable structure is formed from the collection of genes inside a design seed.

Phenotype Emergence

An emergent CAD model will be updated in each growth step based on the genes and the growth algorithm using CADfix software accessed through the API. To successfully grow a design, the genes that represent growth direction, cross-section shape and magnitude are mandatory in a design seed.

Case 1

Lets review the growth of a seed positioned at (0,0,0) comprising of 6 design genes, as defined below.

  • gene1 = [DirectionX,                0,     1,     0.0,   1.5,    1]
  • gene2 = [DirectionY,                 0,     1,     0.0,   1.5,    1]
  • gene3 = [DirectionZ,                 1,     1,     0.0,   1.5,    1]
  • gene4 = [Cross section,   Circle,     1,     0.0,   1.5,    1]
  • gene5 = [Length,                     0.5,     1,     0.0,   1.5,    1]
  • gene6 = [Radius,                    0.2,     1,     0.0,   1.5,    1]

Gene 1-3 specifies the growth direction of the seed and it’s organism when it begins growing. These genes state that the growth vector is [0, 0, 1], i.e. in the Z axis.

Genes 4 through 6 specify the cross-section type, length of each growth step and the size of the radius respectively. The cross-section shape of the geometry is specified to be a circle in Gene 4; the length of each cylindrical cell is set to 0.5m as defined in Gene 5 and the cross-section radius is set to 0.2m as stated in Gene 6.

The active status and dominance for each gene is set to 1, this means all genes are active and no particular gene is more dominate than another. The start and stop conditions for each active gene are given as 0m and 1.5m respectively. These working conditions refer specifically to the overall height of the organism as it grows i.e. the seed will grow into an organism from initial plantation at 0m in height until a height of 1.5m at least is reached.

It is worth noting that the organism will continue to grow when the total height is 1.5m, working conditions are when the height is greater than or equal to the start value and less than or equal to the stop value. Therefore it is only when the height is greater than 1.5m will the organism stop growing, based on all the genes this means growth will stop at step 4 in the growth process.

Iterating through the growth process algorithm and the design seed defined above, a 2.0m high cylinder CAD model will emerge. Figure 2 below shows the growth of the seed and organism from step 1 height 0.0m through to step 4 height 2.0m.

Figure 2 – A design growth from a seed with simple genes

The same growth process as described below is shown in a video below, the size of the organism is bigger (length, radius, height on/off condition) but all other genes are the same.

Video 2 – Growth of a CAD model with 4 growth steps.

Next in Design Genes

These simple rules, principles and algorithms allows for preliminary investigations of the concept. In the next design series, Part 5, we will show a number of results from the implementation and testing of the genes.