If you've ever felt like your game objects are sliding around like they're on a sheet of ice, you definitely need to dive into roblox studio physical properties custom settings to get things under control. It's one of those things where the default settings work okay for a basic brick wall, but as soon as you want to make a heavy boulder, a bouncy trampoline, or a slippery frozen lake, you're going to find the standard presets a bit lacking.
Getting these settings right is honestly the difference between a game that feels "floaty" and cheap and one that feels polished and responsive. Most new developers just leave everything at default, but if you spend five minutes messing with these sliders, you'll see an immediate jump in how your world feels to interact with.
How to actually enable custom physics
The first thing you'll notice when you click on a Part in the Explorer window is that the PhysicalProperties section looks a bit grayed out or non-interactive. To actually use the roblox studio physical properties custom features, you have to find the checkbox labeled "CustomPhysicalProperties" in the Properties panel.
It sounds obvious, but I can't tell you how many times I've seen people trying to change the density or friction, wondering why nothing is happening, only to realize that checkbox wasn't ticked. Once you click it, a little dropdown menu appears, and suddenly you have access to the five main sliders: Density, Friction, FrictionWeight, Elasticity, and ElasticityWeight. This is where the magic happens.
Mastering Density for weight and balance
Density is probably the most straightforward setting, but it has a massive impact on how your game's physics engine treats an object. In Roblox, every material has a default density. Plastic is different from Wood, which is different from Diamond Plate. But sometimes you want a tiny pebble to weigh a hundred pounds, or a giant skyscraper-sized block to be as light as air.
When you tweak the density in the roblox studio physical properties custom settings, you're essentially changing the mass without changing the size. If you're building a vehicle, this is huge. If your car is flipping over every time you turn a corner, it's probably because your center of mass is too high. You can solve this by making the floor of the car incredibly dense and keeping the roof light. It keeps the vehicle glued to the road because the engine treats that bottom part as the "heavy" anchor.
Dealing with Friction and FrictionWeight
Friction is what determines how much objects resist sliding against each other. If you're making a racing game, you want your tires and the road to have a decent amount of friction so the car doesn't just spin out. Conversely, if you're making a slide in a water park, you'll want to crank that friction down toward zero.
But here's the kicker: FrictionWeight. This is something that trips people up all the time. Imagine you have two parts touching—one has high friction and one has low friction. How does the engine decide what happens? That's where the weight comes in. If Part A has a FrictionWeight of 10 and Part B has a FrictionWeight of 1, the engine is going to prioritize Part A's friction settings. It's basically a way of saying "my friction setting is more important than yours." It's super useful when you want a specific "ice" part to always be slippery, regardless of what kind of shoes the player is wearing.
Making things bounce with Elasticity
Elasticity is just a fancy word for bounciness. If you set this to 1, the part will ideally bounce back with the same energy it hit the ground with. If you set it to 0, it'll just thud and stay there.
Just like friction, there's an ElasticityWeight. If you're making a basketball game, you'll want the ball to have a high elasticity, but you might want the rim to have a lower one so the ball doesn't just fly off into orbit every time it hits the metal. By balancing the roblox studio physical properties custom sliders for both the ball and the court, you can fine-tune that "perfect" bounce that feels realistic to the player.
Why Weight sliders matter more than you think
I touched on this with friction, but the "Weight" sliders are really the unsung heroes of Roblox physics. Most people ignore them because the default is usually 1, but they are essential for consistency.
Let's say you're making a platformer where certain blocks are "sticky." You might set the friction to 2, but if the player's character has a default friction setting that conflicts with it, the result might feel jittery. By bumping the FrictionWeight on your sticky block up to 50 or 100, you're telling Roblox, "I don't care what the player's settings are, use this block's friction." It saves you a lot of headaches when you're trying to debug why a mechanic works for some players but not others.
Real-world examples for your game
Let's look at a few practical ways to use roblox studio physical properties custom settings in a real project:
- Ice Skates or Sliding Puzzles: Set Friction to 0.05 and FrictionWeight to 10. The player will slide around like crazy, and it's a blast for obstacle courses.
- Heavy Doors: If you have a door that players need to push open, give it a very high Density. This makes it feel "meaty" and prevents it from swinging open like a piece of cardboard when a player walks into it.
- Trampolines: Set Elasticity to 1 and ElasticityWeight to 100. This ensures that anything landing on the trampoline gets a massive boost, regardless of whether it's a heavy crate or a light player character.
- Floating Objects: If you have a part in water and it's sinking, lower the density. Since Roblox water has a specific density, anything lighter than that density will naturally float to the top.
Adjusting properties through scripts
While most of the time you'll be doing this in the Properties window, sometimes you need to change things on the fly. Maybe a player picks up a power-up that makes them "super heavy" or "super bouncy." You can actually change these roblox studio physical properties custom values through Luau.
You can't just change Part.Friction = 0.5 directly, though. You have to create a new PhysicalProperties object and assign it to the part. It looks something like this:
part.CustomPhysicalProperties = PhysicalProperties.new(density, friction, elasticity, frictionWeight, elasticityWeight)
It's a bit more work than changing a simple property, but it gives you total control over the physical world while the game is actually running. You could make a floor that slowly becomes more slippery over time or a ball that gets bouncier every time it hits a wall.
Common pitfalls to avoid
One of the biggest mistakes I see is people over-complicating their physics. Before you go changing every single part in your game to have roblox studio physical properties custom settings, ask yourself if the default Material property covers it. Roblox has built-in physics for things like Grass, Ice, and Mud. Use those first! Only dive into the custom settings when the defaults aren't giving you the specific "feel" you're looking for.
Another thing to watch out for is setting density too high on moving objects. If you have a scripted platform moving with a PrismaticConstraint or something similar, and you give it a density of 100, the "motor" of that constraint might struggle to move it. You'll end up with parts that jitter or just flat-out refuse to move. Always keep an eye on how your custom physics interact with your constraints.
Wrapping it up
At the end of the day, playing around with roblox studio physical properties custom settings is mostly about trial and error. There isn't a "perfect" number for friction or density because it all depends on the scale of your game and how fast your players are moving.
The best way to learn is to create a small test area with a few different parts, turn on the custom properties, and just start sliding those bars around. See how a heavy block reacts when it hits a bouncy floor. See how a low-friction character handles a high-speed turn. Once you get a feel for how these five sliders interact, you'll be able to make your games feel a whole lot more professional without ever leaving the Properties tab. Happy building!