### Author Topic: Multi Centered Arch Generator (for facades, gates, windows and buildings)  (Read 304 times)

#### Paolo_Giandoso

The node is available on my Artstation page here https://www.artstation.com/marketplace/p/KMlg/substance-designer-arch-generator.
Hi all
This is my first time posting on the "Showcase" part of the forum as I am usually the one pestering people with questions  and I am not by any means a master of the software. I do concept art so I generally use the substances from substance source.
I am also not sure what is the best way to showcase a substance file here on the forum so I am all ears on this issue.
Nevertheless during the lockdown I had some spare time to play with substance designer.
Specifically I kept hearing that the pixel processor is a really powerful node and I wondered what I could do with it and how much could I push it.
I really love those substances that reproduce building facades. I have seen some amazing work.
One thing I noticed though is that there is not really any easy way to create the main types of arches https://happho.com/beautiful-entrance-arches-house/(excluding the 1 centered circular arch), especially when you have to show the voussoirs, or you want a texture (like a wood pattern) to follow its shape.
Therefore I decided to brush my high school trigonometry and give a read to a great book called "Practical geometry for builders and architects".

Math is FUN!
The result of this exploration of the pixel processor was my "Arch Generator" node.
This is a node that can generate all the main types and sub-types of arches and that can map an image input along their length and width. It was a fascinating challenge to tackle and the result, while not 100% perfect, still does what is supposed to do in most of the cases.

For the most difficult cases (the true elliptical and parabolic arches) I had a LOT of help from the math geniuses at MathStackExchange and Inigo Quilez https://iquilezles.org/www/articles/ellipsedist/ellipsedist.htm which involved getting around a nasty quartic equation which I would not wish it upon even my worst enemy. So a huge thank you guys!

My arch generator can simulate the following types of arches:

Flat Arches
- Tapered
- Parallel

1 Centered Arches
- Semicircular Arches (Roman Arches)
- Segmental Arches
- Horseshoe Arches

2 Centered Arches
- Pointed Lancet Arches
- Pointed Equilateral Arches
- Pointed Drop Arches
- Pointed Segmental Arches

3 centered Arches
- Pseudo 3 centered Arches

4 Centered Arches
- 4 centered Arches (Tudor Arches)
- Pseudo 4 centered Arches

5 Centered Arches

Elliptical Arches
- Elliptical Arches with rays perpendicular to the ellipse
- Elliptical Arches with rays passing through the center

Parabolic Arches
- Parabolic Arches with rays perpendicular to the parabola
- Parabolic Arches with rays passing through the center

Ogee Arches
- 3 centered Ogee Arches
- 4 centered Ogee Arches

Reverse Ogee Arches
- 3 centered Reverse Ogee Arches
- 4 centered Reverse Ogee Arches

Multifoil Arches
- With external arch
- Without external arch

Pointed Multifoil Arches
- With external arch
- Without external arch

By default the node generates a basic brick pattern:

But it also works with custom textures.
Here I am plugin a custom height map of a couple ornamental patterns into the node and as you can see it gets remapped along the arches.

I am so curious to see what people will do with it.
My wish would be that if you do some nice facades and gates with the Arch Generator, please share an image here and the substance on substance source so that we can all use it in our concept art
Last Edit: November 11, 2020, 12:23:01 am