I posted about this over on E46 fanatics, but thought I'd share here as well since it's ZHP (MTech II) bumper related.
A few months ago I bought a 3.0L swapped E46 touring that had a MTech II bumper installed. It had a few cracks and some damage that needed repairing, including a broken lower support bracket on the right hand side, and completely missing lower support on the left hand side.
For those not familiar, the lower support / adapter brackets are an integrated part of the bumper cover that are the attachment point for the lower inner finder liners, and make up the gap between the bottom of the bumper and the inner fender.
The ZHP bumper is lower to the ground than the standard bumper so the adapters act as spacers to allow the ZHP bumper to mount to the standard inner fenders.
The adapter brackets are melt-welded to the bumper as a subcomponent of the bumper itself, and are not available to buy separately, even though they each have a unique BMW part number.
Left: 51117893127
Right: 51117893128
So at this point I could have just reattached the RH side bracket with some bumper repair adhesive, but I still needed to source a LH side bracket. I searched for a used one from a broken/damaged ZHP bumper, but came up empty handed. So I decided to make my own.
First, I measured and 3D modeled the RH side bracket using CAD software. Then did more measuring and checking to make sure the model matched the physical part. Once I was happy with the RH side, I mirrored it over to create the LH side.
I used Xometry online 3D printing to have the parts made from Polypropylene (PP), which is the same material as the bumper cover. They were printed using HP Multi Jet Fusion for high resolution and strength.
About a week later the parts showed up in the mail.
And then I glued them in placed with LORD Fusor 143 structural bumper adhesive.
I'm working on a few minor improvements to the model files to make the 3D printed parts more accurately match the real parts, and to improve fit and finish. Once the updates are complete I'll be uploading the final model files for anyone to use to print their own.
I printed two sets of each LH and RH side brackets, so the price per unit was reduced vs printing a single part. With shipping cost factored in, each bracket was around $30.