sphere-spaceship problem

[Doby]

I´am working on a sphere-spaceship inspired by Perry Rhodan, a German Science Fiction Series(novels) (http://www.perry-rhodan.us/index.html - english information site).

The ship will look somehow like this ... http://www.perrypedia.proc.org/wiki/Kugelraumer

My Problem now is, i have 8 liquid engines attached to the middelpart(Fueltank) and the engines 'sink' into the fueltank when i´am accelerating. :\'(

Some pic´s to explain what i mean:

no thrust(everything fine):

more thrust(they starting to 'sink' into the fueltank):

and more thrust(totally disappeared in the fueltank):

my question now is, why they 'sink' into the fueltank? and what can i do so it does not happen anymore? ???

hopefully someone has a solution...

greeting from Germany Doby

(sorry for my bad english)

[Guest Flixxbeatz]

little tweaks more I guess? Looks like the in-game physics has some defects at this time...

[6677]

The collision mesh could be too small or alternatively I believe there is a part of the config file for your part somewhere that defines how strong an attachment node it. I do apologise but I don\'t know what the parameters are called and can\'t seem to find them anywhere

[Guest Flixxbeatz]

The collision mesh could be too small or alternatively I believe there is a part of the config file for your part somewhere that defines how strong an attachment node it. I do apologise but I don\'t know what the parameters are called and can\'t seem to find them anywhere

...or probably it\'s too awesome to be made in-game...

[Doby]

The collision mesh has the same size like the part. I don´t know if there is a config for that. Not in the 'normal' parts. It also dosn´t happen with the liquid engine attached to the 'middel' of the part, only when i attach engines to the outer part of the fueltank...

[crekit]

Increase the impact strength thing.

[Doby]

you mean crashTolerance ? ... That has no effect ...

[NovaSilisko]

Is the collision mesh extending to the outer part of the tank? If there\'s no collision mesh directly under the engines, then they will be pushed through like that.

[Doby]

the collision mesh is a copy of the body and has the same size like the body...

i have testet a little, and that´s what i found out:

when i set the attach node of the 'outter engines' more to the middel, the engine dont sink so much in the fueltank ...

and with the stock engine it dosn´t happen... but looks bad

so i testet to take the original cfg. from the stock engine(maybe a error in my .cfg), but they sink also in the tank...

when i attach my engines to an stock fueltank, the engine dont sink into the fueltank...

also they dont sink into the fueltank when i attach a strutConnector to the engine, but looks also bad...

so i think something is wrong with the engine ... i testet different collision mesh, a copy of the body, and a simple cylinder and also a box ... always the same... the engine sink into the fueltank, deeper when the attach node is more on the outer site of the tank ... in the middle of the tank it dont sink ...

i dont understand my fault ???

[Technical Ben]

Can you use a 12 sided cylinder for the collision mesh? Does that simplify things and stop the stretching?

[Killerhurtz]

the collision mesh is a copy of the body and has the same size like the body...

There\'s your problem I believe. Your model looks hollow. KSP doesn\'t support concave collision meshes yet.

[Technical Ben]

If you want a cylinder shaped part, use a plain 12 sided cylinder for your collision node. Just size it to the top, bottom and diameter of your part.

Else, if you want a truly doughnut shape you will need to cheat. Split your part into 4 (or 6, 8 etc) and make it as a side attachment. Similar to wing parts. Except your will be wedge shaped.

[NovaSilisko]

There\'s your problem I believe. Your model looks hollow. KSP doesn\'t support concave collision meshes yet.

It\'s never going to. Multiple collision primitives per mesh, sure. Concave collision? Hell no.

[Doby]

I have made another testround, and i found out that it has something to do with the mass of the engines.

My engines are lightweights because they are little and have not so much thrust.

That was the only parameter i not have testet until today (i changed this also when i testet it with the stock engine part .cfg)... and with a mass of 2 like the stock engine part... they dont sink into the fueltank! ;D

so i tested it the other way around and make them 'ultralight' with a mass of 0.1 ...the result is that:

The engines not only sink into the fuel tank they go on moving more this direction ???

so... when you have a lightweight engine and the attachpoint is far away from the center of the ship the engine starting to 'moving around' the center of the ship. More thrust, more 'moving'. The effect is larger with lighter engines or attacht points more away from the center ...

Dont know why or if it is a bug... but with mass = 2 everything is allright now.

If you want a cylinder shaped part, use a plain 12 sided cylinder for your collision node. Just size it to the top, bottom and diameter of your part.

Else, if you want a truly doughnut shape you will need to cheat. Split your part into 4 (or 6, 8 etc) and make it as a side attachment. Similar to wing parts. Except your will be wedge shaped.

also an idea i thought about ...

sry again for my english hope you understand it