# Wallacei X Phenotype

Hi Guys!

I have a general Question about an explanation in the Primer.

“3. One of the greatest features of WallaceiX is that it is possible to export phenotypes AFTER the simulation has been complete. This means that it is unnecessary to construct the phenotype in the design problem before running the simulation. Unless you actually need the phenotype to calculate the fitness objectives, construct the phenotype AFTER you finish the simulation (and before you export the selected solutions).”

My question is: isn’t optimization always dependent on the phenotype? For example, if I want to optimize a geometric structure based on certain properties, I always need certain geometric values from the respective phenotype (e.g., intersection point coordinates). So, when do I need to integrate the phenotype during the computation in Wallacei X? I’m not quite clear about that.

Greetings, Ludwig

Yes you are right, the calculation of the objectives are always on the phenotypes. But this phenotype does not necessary refer to a geometry, let me give a simple example. Just imagine you have an objective to maximise volume and your phenotypes are boxes with different dimensions. In this case you don’t need to create Breps to compute the volumes, you can simply multiple the area by the height to get the volumes. In this case you did not create the phenotype to its final stage, you only created it to an extent that it is needed for the calculation of the objectives. When the simulation ends, then you can construct your phenotype in full to export the final results.

2 Likes

Ah okay, that definitely makes it clearer. However, in my case, there are some geometric steps involved: for example, creating intersection points of curves with surfaces. Do I then have to connect these intersection points as phenotypes to the Wallacei X components from the beginning?

or creating a mesh (adjustable by sliders/genes), which is then calculated by Karamba3D to give me a deformation, which in turn is used as a fitness function.

Im still not quite sure wich steps i have to connect as phenotypes

There is no need to connect any phenotypes to Wallacei X component.

1 Like

Ah okay, now it’s clear why there was sometimes a discrepancy in my fitness results. Part of my code is stochastic, and it changed when Grasshopper was restarted, which in turn messed up the stored results from Wallacei.

Thanks for the help, I thought it was due to Wallacei. Now everything works