So, I’m still working on buildng my pprocedural city and have hit a road block in creating block generators.
I started out with a building generator I made following this tutorial: https://www.youtube.com/watch?v=59PeIGmZQdY
It takes user inputs for depth, height and width and creates a single building with those dimensions and instances a wall mesh from a collection onto the vertices. Its all based of generating a mesh cube/dividing the vertices and instanncing on the cube’s vertices.
Here’s a screenshot of the full (messy) node tree.
The tree uses the generated cube’s normals to determine the instance index/rotation/find corners/edges etc and place all the carefully organised elements from a location in the correct places.
So to set about building a block I created a new tree which instances cubes along mesh lines which are scaled based on the plane the node group lives in, and divided by a constant 3m to ensure they are always scaled to fit the dimensions of the mesh walls to be instanced.
I calculate the x annd Y vertices based on their lengths divided by 3
These vertices are derived from the original instanced cube.
However I wanted all my cubes to have random variable heights. As the cubes are instanced, the only way to do that was using Scale Instances node placed after instancing the cubes.
This was all fine, I created a random value to scale in multipples 3m so get an evenly distanced scale.
However, because the height is being randomised after the cubes are instanced, I had to leave the Z vertices at 2 for top and bottom because they would not be spread evenly as the edges of each cube are different.
Plugging the realised output into my building generator worked as expected. However only generated the first floor and roof as there were no vertices down the vertical edges. Still it innstanced everything in the right place - corners, faces, rotating instances for the sides.
So, in order to subdivide my vertical edges evenly, I realised the instances selected only the vertical edges, converted mesh to curve, and resampled them at a 3m distance.
This gave me exactly the sort of vertex structure I needed to instance my walls.
(ICO’s instanced on points.)
So then I converted the resampled curves back to mesh and joined them with the original realised mesh and merged by distance to make sure they become a single mesh island.
However when I plugged it innto the building generator things didn’t quite work as expected.
The ground floor and roof still work as their normals come from the originally realised cubes. However all the middle floors - from the resampled curve are all facing the same direction.
What I think has happpened is that converting the mesh to curve and then back makes all the normals face the same direction, so the calculations my node group has determine instance index/rotation/maskinng isn’t workinng because the nnormals are nnot facing the correct way according to the cube object.
This would make sense as once the curves are converted back to mesh they have no faces.
I’ve tried fill curves, but as my curves are not flat on the z axis it doesn’t work, ad using profile curves creates an unwanted edge justting out of the edge of my cube/building.
Does annyone know how I can ‘fix’ the normals of the edges onnce they’ve been converted to curves and back?
My blend file is here: https://www.dropbox.com/scl/fi/28hluxgvccggsgmu0z4z6/Procedural-Block.blend?rlkey=dqvhv0c4iphmuxvf0zu1p1r4e&st=2z4trnzn&dl=0
