U49 Dynamic vs Static objects W.I.P

Hello in this post i will be discussing the difference between a static object and dynamic object and why you may use one or the other.

Dynamic objects are objects that have dynamic lighting and may also have physics.

However these are lot more GPU (Graphics processing unit) and CPU (Central processing unit) intensive than static as the game has to calculate the lighting on the fly as well as all the physics calculations for when objects hit it or it hits others like a player landing on a moving platform or the moving lights of a passing car etc.

A bouncing ball object has both dynamic lighting and dynamic physics to realistically bounce and collide with objects and to interact with the scenes lighting.

Wheeled Vehicle

A wheeled vehicle object has fairly complex physics to interact with the ground with things like suspension simulations and tire physics. And cars may also cast their own light things like headlights.

Moving door

A moving door is a object which the player can move with ether by a button press or by pushing into it with ether the player itself or another object to ram it open.

Static Objects are objects that do not move and are do not physics objects and may have Pre--baked lighting

A house

EXAMPLE IN ALMOST EVERY GAME

A landscape i.e hills grass rocks

EXAMPLE IN ALMOST EVERY GAME

Furniture

EXAMPLE IN ALMOST EVERY GAME

These for the most part have no reason to not be static and static means these objects are less resource intensive and can make use of tools like occlusion culling which on renders what is in the players FOV cutting down massively on how much power it takes to render.

Bouncing ball hitting a wall

Unreal engine 4 default projectile hitting wall

In unreal engine 4 there is a first person shooter template and gun fires bouncing balls which dynamically cast shadows as well as bounce of solid objects like walls for a couple of seconds before it despawns.

With moving cars interacting with the ground they is a lot of physics calculations that are needed to keep the wheels acting naturally and to stop the game doing things like randomly flipping cars in the air etc as well as also the cars casting a dynamic shadow on the ground and objects they are near at speed they may also light up themselves and objects around them with things like headlights this is why turning down reflections and lighting in racing games makes a huge difference to frame rate as most of it has to be done on the fly.

Flowing water over terrain

Dynamic water simulations for games can be very resource intensive but also can have great results and when you want the most realistic results you need to use dynamic water to get things like objects to float on them properly on things like a river rapids. Normally with fluid simulations they will have a sauce from where the water infinitely flows and then it will flow down with gravity and can have the most natural results with things like waterfalls instead of using canned animations but again this is very resource hungry and cant be used on a lot of projects.

Cities skyline water physics.