How do I create a custom collision polygon for physics

so the question is, can a custom collision polygon be created inside one image?

this is the image:

i.imgur.com/kSRdqBG.jpg

and i want the polygon to be bound on the track's edges. so when a car hits the edge of track to.. bounce and slow down..

my buddy did it with additional ~60 objects with physics applied, but that seems too much and not needed.

any solutions?

Inside the image editor bottom shape on the left is the collision polygon tool..

You are going to need multiple shapes (not 60), because a collision polygon only has an outside, so you can't have an open space in the middle..

I don't know much, but I thinned it down http://imgur.com/SdhnpCv

You can save time like with 1,2,7,8 and 3,4,5,6 using clone object and rotating.

thnx, yes this seems like a very good solution SKuirely.

it would be nice if construct had options for creating more / polygon shapes in one.

also i got another question - why can't i add more points to collision polygon?

You can..

Right click on a polygon point and choose add..

it's greyed out :/

select the point with left click..

when the point is yellow, right click on it and add new point..

oh, that worked, thnx !

Just note - if you are using the asm.js physics then you are limited to 8 polygon corners per sprite...

oh, thnx, didn't know that.

btw. why is it not able to generate "guess collision polygon" for whole animation set? is there a plugin that does that?

i mean if i have a 300 frames animation, i want construct to guess polygon shape for each of them. but i have to do that manually for all 300 frames. is there a shortcut? (i've tried shift + .. but it doesn't work).