Inspired from a number of other projects such as:
https://www.thingiverse.com/thing:2977887
https://www.thingiverse.com/thing:1294085

These are both great projects, but neither had the required number of slots or the height wasn't quite right. Not really knowing what I wanted I created a customisable version in OpenSCAD to experiment.

The parameters allow for most parts the paint brush stand to be modified to accommodate various brushes and tools. I've added the final version I went with as an STL, but feel free to experiment with the OpenSCAD file within the project. Please report on anything produced and issues found!

A brief overview of the parameters used:

• cols, rows : How many x and y holes there are for paint brushes
• holes : Rather than having a single hole / slot this vector contains the starting x and y coordinates where another nxn slots will be placed. The vector has the following form [[x, y, xsize, ysize]]. Multiple holes can be within the same vector as [[x, y, xsize, ysize], [x, y, xsize, ysize]
• stands : A vector of x and y coordinates for each slot that should be covered if the stand is used. This is used on the top piece of the stand. On the bottom piece it also stops a paint brush guide being placed in that particular slot. Multiple slots can be used by having a vector of x and y coordinates [[0,0],[5,5],[0,5],[5,0]]
• thickness : How thick the frame is around the slots. It is consistent for the inside and outside of the brush holder.
• hole_size : The x and y dimension of the paint brush holes. They will always be square.
• frame_height : If not used this will be the same as the hole_size, but it can be different giving a different height to the top and bottom pieces.
• guide_type : a guide in the 1x1 paint brush slots. 0 means none, 1 means square and 2 for rounded. Note for rounded(2) this can significantly slow down model generation
• stand_height : How tall the stand will be.
• stand_tolerance : Reduces the stand size to enable it to fit within the designated slot(s) on the base and top piece.

To replicate the 6x6 model the following parameters can be used:
{
cols = 6;
rows = 6;
holes=[[1,4,2,2],[3,4,2,2]];
stands=[[0,0],[5,5],[0,5],[5,0]];
thickness = 1.5;
hole_size = 10.0;
frame_height = 15.0;
guide_type = 0;
stand_height = 70.0;
stand_tolerance = 0.3;
}

to replicate the 7x7 model with a single stand (albeit without the nice curved edges) the following parameters can be used:
{
cols = 7;
rows = 7;
holes=[[-1,-1,-1,-1]];
stands=[[0,6]];
thickness = 1.5;
hole_size = 9.5;
frame_height = 12.0;
guide_type = 0;
stand_height = 70.0;
stand_tolerance = 0.3;
}