Onwards to development comrades…

The best results often reside in good planning, custom subassemblies are no exception to this. However, if you are reading this you are probably not entirely sure what the best result is going to be.

So here is a process/guide to developing a good CS:

· Start by drawing a cross section of the most typical arrangement. (You may need to draw multiple sections for varying scenarios if they are complex)
Then consider the following

· All the parameters you wish to be able to specify. Width, Depths, Grades, Slopes, Elevations. (Group your parameters using these categories, it makes it simpler to find the correct parameters for the end user)

· Where your centerline will be horizontally, i.e the assembly point. Placing this in the middle of your CS might not always be the best idea. Likewise, using a daylight is not usually a good idea. Typically pick the most fixed point possible on your subassembly. Its also important to consider if your alignment will have sharp curves, picking a point on that will be on the inner part of the curve may help.

· Consider all the surfaces that will be involved in determining the finished geometry. Typically this is only one (Existing Ground/Survey). Try to avoid having more than one if possible, i.e using dummy surfaces. Quite often there are simpler ways to calculate your geometry.

· Next consider the parameters you wish to override using either offsets alignments (width targets) / profiles or 3d linework (elevation targets).

· Next consider if you want to control these parameters by specifying absolute value/relative value. See my article here to understand this concept

· Lastly, consider your point/link/shapes codes. I suggest working in the reverse order though. Determine your materials (shape codes), then derive your point and links codes from these names. As explained in the %Coding your point/link/shape codes lesson% it is easier to just have the user type the material names and have everything else worked out based on these names.

You should end up with something that looks a little like below.

This is merely a guide to planning, but it will help you a lot to layout your plan before you start creating anything. Particular for more complex subassemblies.