Howdy, last night I started working on an engine that could fragment blocks, weld them, then blow them up when an explosion is spawned. The most impressive thing (In my opinion) is the smart-weld, but first let me explain how the system works.
An explosion is spawned, but it doesn’t do anything yet. Then the engine detects this explosion and begins to start this
Step 1: Find all parts near the explosion that have a mass greater than 12, then add them to step 2
Step 2: break parts into half size of each axis, so a Vector3.new(2,2,2) part would be Vector3.new(1,1,1), insert these into “model”, then repeat step 1
Eventually step one finds no parts nearby that are greater than 12 mass, so it converts to step 3.
Step 3: “Smart-weld” all of the parts in model, if the part is less than 12 mass then add it to debris in 10 seconds, if not then use a smart formula to weld to the most appropriate nearby blocks. (instead of just welding to the closest blocks, it welds to the biggest blocks nearby in proportion to the initial blocks mass, if that makes any sense)
Step 4: Un-anchor everything in the model so its held together by the smart-welds now, and now start a REAL explosion with an actual BlastPressure where the original explosion was, the fragmented parts are now thrown about.
Game: [Frostblox Engine] Demo - Roblox
PS: Press 3 o select the RPG, or press v to place an explosive barrel, so you can see the destruction!
Edit: engine is now super smooth!
It is allot of fun just blowing stuff up 
