Lag is so hard to build around and I try not to think about it too much when I am first creating.
The problem with lag is ts totally dependent on the users computer/network/internet/3DX Messy game code
Some people have Super computers, Some people have Laptops that still run on Windows XP....
Some people have Super computers but run the 3DX with Spotfiy/Nexflix/Black Desert/Far Cry5/Emails and 15 other programs running in the background...../me frowns
The only real advice I can give is:
3DX handles light badly so try to avoid using to many. (Less than 8)
Reflecting surfaces are an issue because of the way the game handles light. So Glass and Metal surfaces should be used carefully
Objects intersecting with each other. If you have 100 tubes forming a circle and they all cross in the middle...it can cause lag where the props intersect/collide
Tip: When you have finished your build, spend one hour looking around for those hidden props/blocks that are not needed and delete them.
And the Size of the Room. Although this effect can vary. General Rule try and keep your build no more than a 1Mb file. However I have builds that are 2Mb that do not lag... but they are "Simple" in their design.
So the only real advice is to just keep lag as a consideration when you are creating your build...but do not let it dictate it.
Also open your build to your friends and get feed back from them about lag...make make sure one of your friends has a low powered computer. There is no point testing for lag if all your friends have Super Computers
It would be a shame if the only consideration for building is lag...
Build because your creativeness wants you to (and just keep lag as a consideration later)
Ayon