Hi Phil,
I would recommend that you perform a "calibration" of your resin printer with your chosen resin.
You might find that you need to adjust the default shrinkage settings in the Templot export to get accurate prints.
At least I did.
I found the easiest way to perform this was to create a short piece of plain straight track in templot and use this to export a .TSL file, then fix the file using the link that Martin supplies on the epxort page before slicing in chitubox & printing.
Having cured the trackbase you can then measure the sleeper lengths, the sleeper thickness and the overall length of the sleeper base to the outside edges of the end sleepers..
If not as expected adjust the Templot default shrinkage settings and repeat process.
This is similar to the printer calibration that Martin has supplied for inkjet & laser printers, but you have to do a bit more work yourself to achieve it.
Printer Calibration
Starting with a new trackpad, I have set gauge to P4, and chosen plain track set curve to "/" (which gives straight track), then set length to 110mm (suits my Mars 2 Pro printer), switched on experimental chairing, and switched on timber numbering in trackpad. The sleepers are a scale 8'6" (34mm), and the distance between te outside faces of A1 and A12 sleepers can be determined by difference in x centre position of timbers A1 & A12 plus the width of a whole sleeper. 106.00 - [-0.17] + 3.33 = 106.5.
Tick the bricklaying box and the colour box, then "store and background" the template.
Click DXF/STL file export
Tick "timbering brick only" (top left), untick "add brick label text".
Click [timbers only] (middle right) and you get this so far:-
Click [timbering sizes ] button to see all the default settings for the timbers. in particular note "3D timber depth (thickness) of 3.24mm
In the bottom right hand of the screen select the 3-D for resin radio button
You can click the [above shrinkage settings} button to see that on the third page of these setting Martin has defaulted the resin shrinkage settings for all 3 axes to 0.25% (x,y,z)
Now click on the [rebuild now] button (for 337c at least) before clicking on the green [Export DXF/STL file] button
Perform the [repair STL file onlline] process
Slice the "fixed" version of this file (aligning it with the longest dimension of the build plate) and then print it.
Cure it.
Measure it.
Compare the measurements with the target measurements of 106.5mm, 34mm and 3.24 mm.
Adjust shrinkage% settings as necessary & repeat.
I chose 110mm as a target length of template to comfortably fit my builld plate size of 120mm by 80mm, so you might have to adjust this depending upon your build plate size.
Hope this helps
Steve
box file attached