LAYOUT GENERATOR

The city layout tool has most of the core functionality complete, there are some improvements and fixes to be made but overall it's pretty much there.

BREAKDOWN OF BUILDING SPAWNING LOGIC:

As previously mentioned the tool starts with all the blocks that were created based on the roads and runs over them all in a for each loop. To prepare it for generation, it converts the polygon into polylines and scatters points along the edges.

FIRST SUB LOOP

The first subloop handles selecting points, drawing lines, and assigning building rules for building sets.

The tool essentially is trying to spawn sets of the same building types. It starts by attempting to spawn building sets that require and fill in the most space and then works backwards with filling left over space with smaller building sets and eventually singles.

1.

The loop itself starts with a manager that determines how many times to run the loop based on the block area. Larger blocks run the loop 2 times allowing for more building sets to spawn and larger more space consuming patterns to spawn.

2.

Once the tool decides how many iterations it will perform it goes on and selects a random primitive (each line is a primitive) and then once its selected the primitive it selects 2-3 adjacent points to then draw the lines from.

3.

It then goes to the draw mode manager and selects what draw mode to apply to the lines based on certain rules.

• It can select 3 draw types: basic, draw 45, draw z.
• It can ONLY select draw z if the loop has 2 iterations and it is on the first iteration.
• otherwise it can select draw basic and draw 45.

It then funnels through the wrangle for each respective draw mode, drawing the lines.

4.

It then assigns the building rules in an array that will be read later by the building spawning logic.

• The first slot in the array represents the draw mode (basic 0, 45 1, z 2,)
• The second and third represent the min and max story numbers the building can spawn with.
• And anything in the fourth and beyond are the index numbers correlated to the building footprint node’s footprint types.

BUILDING SPAWNING LOOP

5.

It then goes into a building spawning manager node and reads the building rules array to determine what path to take depending on what the first number in the array is.

6.

It then follows the respective path of each draw mode, each draw mode does do some things slightly differently but overall they all have most functionalities in common:

• They remove all inline points along the drawn lines.
• They cut the lines, making them separate prims
• They then “carve” allowing for space between each line.
• They then select the “spawnable points” (some are already there, some are added then selected.) and kill everything else leaving only a single point per prim that stores the building rules, length (length is based on the line length, not defined in building rules)etc…
• Then a node reads the building rules on the point and informs the Footprint Generator node on what to do based on the info. Then the generated footprints are copied to the spawning points.

Then you have a lovely procedurally generated city!

• Everything also has random seeds linked to them to allow for the user to ‘re-roll’ stuff.
• The user can also change the thresholds for the block area to change certain pattern spawning behaviour.

FUTURE IMPROVEMENTS

• Ensuring that no building overlap occurs, The generation does have collision and encroachment detection and 90% of the time it's fine, but because the node is looking at the borders after they have had the corners deleted, if a building line happens to be drawn too close to a corner it might slip through. So usually it's fine but occasionally buildings will ‘escape’, I will have to adjust this.
• Adding singles, right now everything spawns sets, but to be more accurate to the reference there would be 1 off buildings, I would have to add that functionality to the spawning, however due to the time this took to complete that might not happen, but if time allows I will add it.
• There are also some issues with the logic in spawning the “basic” buildings where if multiple basic draw type buildings spawn in a block it connects them in a weird way causing issues.

BAD BUILDING BEHAVIOUR SHAMING SECTION