For one: structural engineering for the bricks themselves that makes them even less likely to bend, break or warp, while still being compatible with other interlocking brick systems (Lego infamously has “illegal” building practices that are only suggested to not use becsuse they put undue stress on the bricks; a lot of 3rd party bricks are made for these “illegal” moves). Some are also easier to remove without seperator tools while still being strongly connected for builds.
For another: You can make shapes and colors Lego doesn’t have at all.
The best ones are from resin printed designs. FDM printed bricks can get fucked up more easily and have other issues stemming mostly from how they are printed (burs, uneven surfaces, etc).
I’ve got thousands of dollars worth of Lego spanning over 30 years and have never had pieces warp before. I’ve had a few 1x plates break over the years (completely my fault) and have also had issues with the notorious reddish brown bricks crumbling, but that’s it.
I’ve also been 3D printing going on 6 years now and even a top of the line printer will have orders of magnitude worse tolerance than an injection molded Lego brick. FDM is around 500um, resin is around 100um, and Lego is <10um and has been for 50 years. This also ignores quality issues from lack of printer maintenance, support material, and the inherent weakness of printed layers versus injection molding (not to mention the difficulty and expense printing ABS).
Getting different colors and shapes is nice but there are companies that make custom Lego bricks doing that too. The only things I ever even consider 3D printing are wall mounts for my space sets/Star Wars ships and giant minifigs.
For one: structural engineering for the bricks themselves that makes them even less likely to bend, break or warp, while still being compatible with other interlocking brick systems (Lego infamously has “illegal” building practices that are only suggested to not use becsuse they put undue stress on the bricks; a lot of 3rd party bricks are made for these “illegal” moves). Some are also easier to remove without seperator tools while still being strongly connected for builds.
For another: You can make shapes and colors Lego doesn’t have at all.
The best ones are from resin printed designs. FDM printed bricks can get fucked up more easily and have other issues stemming mostly from how they are printed (burs, uneven surfaces, etc).
I’ve got thousands of dollars worth of Lego spanning over 30 years and have never had pieces warp before. I’ve had a few 1x plates break over the years (completely my fault) and have also had issues with the notorious reddish brown bricks crumbling, but that’s it.
I’ve also been 3D printing going on 6 years now and even a top of the line printer will have orders of magnitude worse tolerance than an injection molded Lego brick. FDM is around 500um, resin is around 100um, and Lego is <10um and has been for 50 years. This also ignores quality issues from lack of printer maintenance, support material, and the inherent weakness of printed layers versus injection molding (not to mention the difficulty and expense printing ABS).
Getting different colors and shapes is nice but there are companies that make custom Lego bricks doing that too. The only things I ever even consider 3D printing are wall mounts for my space sets/Star Wars ships and giant minifigs.