The layout problem
A local pool installation and landscaping company needed to build a block retaining wall around a circular hot tub. The challenge was working out where the blocks should sit on the surrounding patio while following the tub's shape.
This called for a tool made around the actual installation. I designed a scribing jig that fits across the tub rim and brings a marking point down to patio level, helping transfer the profile to the surface where the wall would be laid out.
From jobsite photos to CAD
I started with reference photographs taken from several angles and measured the distance from the ground to the top of the tub. Including a measuring tape in the photographs gave me a reference for the design work.
In FreeCAD, I used those photographs and measurements to model the jig's profile. The shape bridges the rim, with a longer leg reaching down toward the patio. I then checked the design dimensions against the measurements taken on site.
Jobsite photographs and measurements guided the FreeCAD design.
Printing the jig
I printed the part in PLA on the K2 Plus, using the larger printer for the size of the tool. It was laid on its side without supports, with five walls, five top and bottom layers, and 15% cubic infill.
After printing, I inspected the finished part and found no issues before handing it over for jobsite testing.
The project-specific PLA jig fitted across the hot tub rim.
Putting it to work
The jobsite photographs show the jig positioned across the hot tub rim, with a pencil held at the foot of the longer leg to mark the patio. Working around the tub lets the tool transfer the profile onto the paving below, providing a line for the wall layout.
The foreman tested the jig and gave positive feedback. It is a practical example of using custom CAD and 3D printing to solve a specific problem on site.
The printed jig transfers the tub profile down to the patio for wall layout.
A possible next version
This jig was made for one installation. A proposed improvement is an adjustable telescopic drop leg so the same design could be used with identical hot tubs installed at different finished heights.
For now, this project shows the original custom tool and its use on the jobsite. It is part of the design work I do at Q3D Solutions: taking measurements, understanding the task and creating a part around it.
Have a jobsite problem that needs a custom part? Get in touch with Q3D Solutions to discuss it.