# Physics versus collisions - which is the proper way

**URL:** <https://forums.unrealengine.com/t/physics-versus-collisions-which-is-the-proper-way/467520>\
**Category:** World Creation\
**Tags:** ball, collisions, bounce, unreal-engine, Physics, question\
**Created:** [July 1, 2020, 7:33pm UTC](https://forums.unrealengine.com/t/physics-versus-collisions-which-is-the-proper-way/467520 "2020-07-01T19:33:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![plasticMAYHEM](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@plasticMAYHEM](https://forums.unrealengine.com/u/plasticMAYHEM)\
**Post date:** [July 1, 2020, 7:33pm UTC](https://forums.unrealengine.com/t/physics-versus-collisions-which-is-the-proper-way/467520/1 "2020-07-01T19:33:41Z")

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ok so its the age old question - that has not been answered yet.  
no documentation on it and i’ve been searching all day, trying to use any keywords i can think of.

OK so i checked the “use physics” box, its on a mesh sphere - its just supposed to spawn as a ball  
bounce around etc - i figure checking the box does this automatically though its odd that theres no physics options ?  
aside from gravity etc, which is apparently not physics

ok so when i compile i got 2 errors for “you can only do this one way not both ways”  
so i did see in a post that i can go to the collision panel and turn that off, though it doesnt have a turn off button specifically

that gets rid of one of the errors but not the other one - and i click on the error coz it knows where it is  
and it does nothing for me

how is something integral like this completely undocumented? does anyone even make games with unreal?

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**Author:** ![Everynone](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/everynone/32/1135017_2.png) [@Everynone](https://forums.unrealengine.com/u/Everynone)\
**Post date:** [July 2, 2020, 8:44am UTC](https://forums.unrealengine.com/t/physics-versus-collisions-which-is-the-proper-way/467520/2 "2020-07-02T08:44:51Z")

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What are you trying to do again?

> though its odd that theres no physics options ? aside  
> from gravity etc, which is apparently not physics

What physics options are you after?

> ok so when i compile i got 2 errors  
> for “you can only do this one way not  
> both ways”

Is this the actual error message the editor is throwing?

> so i did see in a post that i can go  
> to the collision panel and turn that  
> off, though it doesnt have a turn off  
> button specifically

Turn off what?

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**Author:** ![Everynone](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/everynone/32/1135017_2.png) [@Everynone](https://forums.unrealengine.com/u/Everynone)\
**Post date:** [July 2, 2020, 8:49am UTC](https://forums.unrealengine.com/t/physics-versus-collisions-which-is-the-proper-way/467520/3 "2020-07-02T08:49:43Z")

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> physics versus collisions - ok so its  
> the age old question - that has not  
> been answered yet. no documentation on  
> it and i’ve been searching all day,  
> trying to use any keywords i can think  
> of.

You can’t have physics interaction without collision.

> how is something integral like this  
> completely undocumented?

The documentation is actually pretty good considering some other engine features (i’m talking about you random sobols):

> **[Physics](https://docs.unrealengine.com/5.3/en-US/physics-in-unreal-engine/)**
>
> Subsystem that calculates collision and simulate physical actors.

> physics versus collisions

The _Simulate Physics_ bit is what you’re after, most likely.

 ![306005-annotation-2020-07-02-095512.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/f/9/8/f98f73671e1e803e6d361d246e178b1a2ffabbc4.jpeg)

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<div class="post-metadata">

**Author:** ![Everynone](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/everynone/32/1135017_2.png) [@Everynone](https://forums.unrealengine.com/u/Everynone)\
**Post date:** [July 2, 2020, 9:01am UTC](https://forums.unrealengine.com/t/physics-versus-collisions-which-is-the-proper-way/467520/4 "2020-07-02T09:01:51Z")

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> […]aside from gravity etc, which is  
> apparently not physics

One can also hold `ctrl+alt` while hovering over an option to expand the tooltip and access more info; there’s often a direct link to the pertinent documentation page:

 ![306007-gravity.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/7/c/8/7c8c495cec897e8e5e3256f111c61dec44daa92e.png)

Hope it clears things up a bit.

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<div class="post-metadata">

**Author:** ![plasticMAYHEM](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@plasticMAYHEM](https://forums.unrealengine.com/u/plasticMAYHEM)\
**Post date:** [August 24, 2020, 4:01am UTC](https://forums.unrealengine.com/t/physics-versus-collisions-which-is-the-proper-way/467520/5 "2020-08-24T04:01:43Z")

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oh hey thats the kind of thing i need. i just found this post, after this many weeks.

im still on my, two weeks to make a game.  
but getting user interface down is a week and now i see i have to get oriented too.  
so once im oriented im just doing 100 things in one room all on top of each other right now.

once i get that two weeks for a game id say.  
i dont see why i cant say im #1, if i follow 200 tutorials anyone has a game right.  
so how cant i be 1. f\*\*\*