These accessories work with Vevor plastic trench drain hardware (100mm x 100mm), though it is designed in OpenSCAD, so the configuration should be easy enough to adapt to other flavors.  I recommend some RTV silicone or caulking to seal the seams before final placement to prevent leakage.  I printed this with ASA which likes to warp so I used a thicker brim around the right angle adapter that seemed to largely prevent warping.  Two STLs, one with the manual brim and one without are provided based on your preference.  I printed all other parts with a 20mm brim for the same reason, but if you are using different filament it may not be required.

Files:

• VevorTrenchDrainRtAngle-WithManualBrim.stl
  Right angle adapter with 2 layer brim for adhesion/stability during printing
• VevorTrenchDrainRtAngle-nobrim.stl
• Right angle adapter without brim, can be added during slicing
• VevorTrenchDrainRtAngle-grate.stl
  Grate for the right angle adapter
• VevorTrenchDrainRtAngle-3inchPVC.stl
  3" PVC pipe adapter for trench drain.  This fits into the PVC pipe at the bottom of the channel to prevent standing water in the trench drain.
• VevorTrenchDrainRtAngle.scad
  OpenSCAD source file for above STLs  See “Visibility” section to adjust what is shown by setting variables to 1 for show and 0 for hide.  This should also place parts in printing positions if selected individually or in their functional locations if multiple parts are shown

Print Settings:

• ASA Filament (for outdoor ruggedness)  PETG or ABS would probably also work
• 0.4mm nozzle
• 0.2mm layer thickness
• 3 top and bottom layers
• 4 perimeters (helps with ruggedness)
• 20 mm brim if not printed with manual brim to prevent warping
• 4 perimeters for stability
• 15% or greater infill; 15% works for me but the print will be stronger with a higher % infill