This is not an addon, the download file contains a Blender file with the geometry nodes tree and all the assets.

“Procedural Alleys v1.0” is a pack that contains both geometry nodes with which you can create building walls with just some clicks and high-performance assets.

These assets are the parts of the two types of alleys that you can build with the geometry nodes.

How to use

To get started, simply unzip the zip file, which includes the Blender project. From there, open the original Procedural Alleys file and copy the alleys to your scene. Either way, all the collections used by the geometry nodes will be copied to your project. We recommend that you move all of these collections into a new one and hide it.

You can also append the alleys collection as we show in the tutorial video:

Procedural Alleys v1.5 Tutorial

The project contains three buildings. There are also three different geometry nodes that you can use.

The first GN generates a building with a front alley and two lateral alleys. In order to reduce the modifier settings, the two lateral alleys are the same wall mirrored.

The second GN only generates the front alley, and the third one generates one lateral wall (back alley).

You can use these two last nodes when the other faces of the building don't appear in the render to reduce the polygons in the scene and the render times.

The third GN “003.ProceduralAlleyOnlyLateral” has an extra feature that allows you to generate cables between buildings.

As you can see, you can enable or disable these wires with the “Enable Cables Between Walls” setting. 0 is disabled and 1 is enabled.

This feature works using raycast in random directions from the wall to another hidden plane, you can modify the distance between the wall and this plane, then you place another GN wall in front of the first at the same distance that you define in the “Distance” setting.

As I said, I use raycast to generate the cables in random directions; this is why the lower the value of the Distance field, the higher is the probability of the raycast colliding with the plane, so you may need a lower Density. Be careful if the Density value is high and you reduce the Distance value a lot because this can make Blender crash.

Tip: Set the Density to a lower value, set the Distance how you need, and then increase the Density value.

How to add your own assets

If you want to replace the original assets with your own, the easiest way is to go to the Outliner, search the collection which contains the assets that you want to replace (Windows, for example), and delete or move to another location the assets and put in there your assets.

Some assets, like all the assets inside the “Shops” collection, have lights or other elements which do not mesh; in those cases,, you have to group all the elements which conform to the asset in one collection. The collections inside the main collection work like one unique mesh, one unique asset.

In order to keep the geometry nodes modifier without a massive amount of parameters, there are no settings to replace the collections. Still, in the case that you prefer to replace the collection instead of just replacing the assets inside the original collection, you can do it in the geometry nodes window, searching the “Collection Info” node and replacing the collection with another one.

Assets measures:

In the case you want to replace the assets, there is one group of assets that must have a specific measure:

The above assets must have the indicated dimensions.

The assets which connect on the top and below parts with others must have 2 meters height.In the same way, if connected on the right and left sides must have 4 meters width.

The rest of the assets can have different measures; for example, to add new signs, the only thing that you have to keep in mind is that the height must be lower than the window's height in order to not collide with other elements.

Things to keep in mind when you replace or add your assets

Assets origins:

When you add your own assets, you have to keep in mind that the geometry nodes instances assets from their origin, so it is important to set the origin in the right place.

The easiest way to know where the origin should be is by watching the original asset, which you will replace and set the origin at the same point.

For example, the signs can be 2 meters in height maximum, and the origin must be in the back and bottom part of the model,

Important: You have to apply scale and rotation. Also, if the asset is not in the right position when using geometry nodes, the problem could be that the original asset must be in the origin of the world, this is not a mandatory rule for all the assets but if you want to be sure, place it in the world origin.

The assets which are made with more than one element, like the shops' collection assets, has as an origin point the origin of the world, so you have to place the items with this in mind.

Lateral wall (Back Alley) assets:

The bottom part of the lateral wall (back alley) uses a Bounding Box Node to calculate the boolean in combination with the assets in the cases when that asset has depth and passes through the wall (like the doors).

The Bounding Box Node generates a cube with the max width, height, and depth of the asset, and with that cube, the boolean is calculated, that’s why if you add an asset that will go through the wall it must have a cube shape. This doesn’t matter if the asset is ahead of the wall.

For this alley, the bottom and the top wall are created and textured procedurally, if you want to change the image texture of this material go to shader nodes and replace the image:

Top Wall material: top_lateral_wall_mat

Bottom Wall material: bottom_lateral_wall_mat

Assets order matters:

In some cases, the order of the assets inside the collection is important because the first asset corresponds to the top part, the assets of the middle correspond to the middles wall parts, and the last assets correspond to the bottom asset:

This happen in the following collections:

• Lateral_Vertical_Assets

• Large_Floor

• Small_Floor

In the floor collections case, the collection contains a corner pavement asset and the “center” of the pavement. If you replace it, the first asset must be the center and the second the corner.

On the rest of the asset collections, the asset order doesn’t matter.

Apply geometry nodes modifier:

To apply the modifier, navigate to the final parameter of the geometry nodes labeled "Realize Instances" and adjust it to 1.

After doing this, apply the modifier:

Now, the materials on the building are incorrect. To fix this, go to the Object Data Properties tab and open the Attributes panel. Click on 'UVMap' and then on the drop-down arrow on the right side.

Select 'Convert Attribute'.

Change mode to "UV Map" and click OK.

Before render:

This is a geometry node tree that instance a lot of different assets and have to calculate a lot of operations to place everything in the right place, in order to reduce the memory used by Blender when you are working on the project and also rendering I optimize all the textures used by the assets to increase the performance.

Despite this, creating massive buildings can make Blender crash on render, to reduce the probability of crashing I recommend you to let the viewport in solid mode, this reduces the use of memory on your PC.