You can write your topic however you want, but you need to answer these questions:
What do you want to achieve? Keep it simple and clear!
I want to know if there are ny tips or tricks on how to have a lot of build and decal detail without slowing the game too much and making it lag.
What is the issue? Include enough details if possible!
The issue is I don’t have a lot of experience building large games.
What solutions have you thought of so far?
I was thinking that maybe importing meshes and adding a decal as a texture would be helpful instead of having builds with a bunch of blocks and different textures would help.
Hey, I don’t have a lot of tips, but quality over quantity, right?
Keep your models simple while maintaining a comfortable look, hence keeping triangle count low. Triangles are the things that the players see, unlike vertices, which don’t really matter when it comes to optimizing.
Use a third party application like Blender to export models, clean them of useless triangles (such as things that the player can’t see), and re-import them as a meshpart into Studio.
Use a streaming mechanic, such as StreamingEnabled which only loads parts of the worlds the player is currently in, you can find the Documents for it here: https://create.roblox.com/docs/workspace/streaming
Avoid having too many parts in one spot, instead consider, as talked about above, turning them into meshparts.
Optimize your code. Bad code can impact game performance and FPS just the same way bad optimization with models can cause harm to performance.
Unioning is one of the worst performance eaters if they are used in high quantities, try to keep unions to the very minimum.
Do not place decals on transparent parts.
That’s all I really have, and I hope it assisted you with your projects.
If you haven’t already, I would strongly recommend enabling the StreamingEnabled property under workspace. It’s really good at keeping the lag down for detailed builds.
New games have it automatically enabled, but this change was implemented quite recently so you may need to enable it yourself.
I doubt they’d be bad if they are used only on simple shapes like blocks and wedges, kept to box or hull. Especially if the parts overlap since unions remove inner faces. It’s why you DON’T want to union spheres/cylinders often if you want good performance.
I’m gonna guess though that chopping off unused parts of a sphere (like making a half sphere) can make it slight more performant because half the polygons are deleted (even despite a few faces on the back. Meshes can likely be slightly better using these tips though.
