Craft collides with itself

[4x4cheesecake]

Hey

I'm currently working on a new orbiter to continue the shuttle challenges and I ran into a problem with my wing design.

The first version of the craft got wings which are build like stripes:
 

Spoiler

Basically I've connected a wing part to the body and build several wing parts on top of it. This version flies pretty well, but atmospheric maneuvering creates a gap between the stripes, even though there are several autostruts (grandparent) and regular struts (clipped into the wing) to connect the stripes.

So I've tried to fix the gap by building just a single stripe and connect alle the other wing parts to the stripe and each other (the arrows show how the parts are connected):

Spoiler

Autostruts (Grandparent) are used to connect the parts. Nothing else got changed but this version doesn't fly at all. I can accelerate to the end of the runway but as soon as the orbiter lift off, the wings break apart. I managed to create a screenshot of the flight protocoll during the first moment of the crash:
 

Spoiler

Apparently, two wing connector crashes into the cargo bay...but how is it possible? AFAIK, a craft cannot collide with itself and parts just 'glitch' through each other.
And also: Any idea how to fix this? Is there a better way to build large wings without getting gaps between the parts?

The orbiter is build in KSP 1.4.3 without any mod parts, so if anyone want to try it:

V1 (stripes) : https://www.dropbox.com/s/kulpv2l9fnazvn3/Orbiter v2_1.craft?dl=0
V2 (connected parts): https://www.dropbox.com/s/iwyrstp18uabiwh/Orbiter v2_2.craft?dl=0

Actiongroups:

• 1 = Toggle Cargobay door
• 2 = Toggle Vector engines
• 3 = Toggle Aerospike engines
• 4 = Toggle chutes

To lift-off, use the aerospikes to accelerate and fire up the vectors ~10m before the runway ends.

edit: Even though my craft can lift-off again, I'll keep the topic as 'not answered', since I'm still curious why there is no flight protocoll entry for my wings breaking apart and if there is a better way to build large wings

 

Edited July 19, 2018 by 4x4cheesecake

[Vanamonde]

Did they perhaps break off and then, as separate objects, collide with the ship? 

[4x4cheesecake]

2 minutes ago, Vanamonde said:

Did they perhaps break off and then, as separate objects, collide with the ship? 

Is it possible for parts to break off without creating an entry in the flight protocoll? Usually I can find something like 'high gee forces' or 'aerodynamic forces' as a reason.

[4x4cheesecake]

@Vanamonde Actually, it looks like you are right. I've recoreded a short video of the launch and went through the video frame by frame.

Here are frame 994 and 995:
 

Spoiler

Since the wings are connected to the body in just one point, the autostruts are not enough to stabilize the whole wing, so the front part of the wing lift while everything else keeps going straigt forward (inertia and stuff...). While in the first frame, the connection between wing and body is still intact, it breaks in the second frame and the parts start to crash into each other.
Btw: Not even the 'unbreakable joints' cheat option prevents the wings from ripping apart.

[Gilead]

Hi! Maybe you could use the welding mod to weld all the parts of the wing together. That way, your wing will act as one big part and won't break, I assume.

I say this, but I have never done it, it's pure speculation. Worth the try I think.

Edited July 13, 2018 by Gilead

[4x4cheesecake]

14 minutes ago, Gilead said:

Hi! Maybe you could use the welding mod to weld all the parts of the wing together. That way, your wing will act as one big part and won't break, I assume.

I say this, but I have never done it, it's pure speculation. Worth the try I think.

I guess you're talking about his mod?

Well, I'll give it a try but wings are part of the 'known issues' lists...I'm curious anyway^^

[Gilead]

Yes, that's the mod I was talking about! (I don't know how to link mods, sry)

I remembered it had parts that can't be welded like RCS or science experiments, but I was sure wings were not on the list. I should have checked, sorry.

[Rocket In My Pocket]

Have you tried real struts?

Autostrutting is great but for some uses it's no replacement for the good ol' fashioned actual honest to goodness real physical strut.

You may find some real struts connecting the wing to the body will give you the structural integrity that autostruts aren't. Worth a shot!

Edited July 13, 2018 by Rocket In My Pocket

[4x4cheesecake]

3 minutes ago, Gilead said:

Yes, that's the mod I was talking about! (I don't know how to link mods, sry)

I remembered it had parts that can't be welded like RCS or science experiments, but I was sure wings were not on the list. I should have checked, sorry.

To link a mod or another forum thread in generell, just copy&paste the URL in your post. The forum software will do the rest for you
Don't feel sorry for suggesting an idea...it might not be an solution but help is always welcome Since the issue list says 'It can be buggy', nobody knows if it helps anyway unitl i've tried it^^

[4x4cheesecake]

2 minutes ago, Rocket In My Pocket said:

Have you tried real struts?

Actually, I've tried them just in the first 'stripe' version (and the result was not as expected). In generell, I often experience some troubles with real struts, especially when using the 'move' tool on them. In example: I have a rover (used it during a challenge lately) with several struts and every time I load the craft, the struts are misaligned. You can see in the picture, that one strut is connected to the science storage module in the back, but the strut actually should connect to the edge of the bottom platform behind the module. And on the left, 2 struts are connected to the middle of the girders (between the solar panels) but they are not aligned anymore.

I'm actually afraid that this will happen to the wings aswell and I have to replace all the struts everytime I load the craft.

I'll try it anyway, maybe a good comination of real- and autostruts will help.

[Vanamonde]

It's actually rare for forces to get so severe that parts rip off, so I don't actually remember whether there's a report entry for that.

[Gilead]

Well, if you try the welding mod, I'd be very interested to know if it worked or not.

[4x4cheesecake]

@Gilead Maybe I'm just dump or the mod doesn't work very well. Tried it for ~30min to weld the parts together but I cannot find a way to select all parts. I also uninstalled 'Editor Extensions Redux' since this mod shares the keybindings with the selection tool of the welding mod, but even than I was not able to select more then 2 or 3 parts.

@Rocket In My Pocket I've added some real struts, changed some autostruts to 'root' (the MK3 Cockpit) and now my craft can lift-off again. Still afraid that some day the the struts will just poke out of the wings

@Vanamonde I ripped off wings of several planes when trying to do these 'High Gee Adventure' contracts and AFAIR, all these wings got an entry for breaking apart due to g-forces.

[Gargamel]

23 minutes ago, 4x4cheesecake said:

@Vanamonde I ripped off wings of several planes when trying to do these 'High Gee Adventure' contracts and AFAIR, all these wings got an entry for breaking apart due to g-forces.

Hmmm.... I seem to recall aero forces braking things too, but I don't know if it applies to wings.

But Generaly, a ship can't collide with itself.    Things just clip and keep on going. 

[Gilead]

21 minutes ago, 4x4cheesecake said:

@Gilead Maybe I'm just dump or the mod doesn't work very well. Tried it for ~30min to weld the parts together but I cannot find a way to select all parts. I also uninstalled 'Editor Extensions Redux' since this mod shares the keybindings with the selection tool of the welding mod, but even than I was not able to select more then 2 or 3 parts.

Well, you don't select every part one by one. Your select a part and the welding will weld this part and all its children, grandchildren etc. So you design your wing like you did on the second screenshot, hit the welding icon, ctrl+click on the "root" of your wing, and hit [weld it]. You then have to reload the game and the wing will be available as a part in the category you chose when welding it.

[4x4cheesecake]

10 minutes ago, Gilead said:

Well, you don't select every part one by one. Your select a part and the welding will weld this part and all its children, grandchildren etc. So you design your wing like you did on the second screenshot, hit the welding icon, ctrl+click on the "root" of your wing, and hit [weld it]. You then have to reload the game and the wing will be available as a part in the category you chose when welding it.

I knew it, I'm just dump
Ok, tried it again and finally got a single big wing (I've removed the wheels and control surfaces before welding the parts together). Unfortunately, the result got some flaws, the first one is visible in this screenshot:
 

Spoiler

I've activated the aerodynamic overlay and apparently, the lift vectors are far away from the wings. Also, I wasn't able to lift-off, the wings were ripped off as soon as I've reached a speed of ~90m/s.

[Gilead]

Well, now we know it doesn't work^^

[4x4cheesecake]

25 minutes ago, Gargamel said:

But Generaly, a ship can't collide with itself.    Things just clip and keep on going.  

I know and that's why I was confused about the flight protocol (actually there is no log entry for the initial joint breaking at all, checked output_log and KSP.log as well). Without recording the video and looking at it frame by frame, I would be still confused^^

[Xd the great]

I believe that attaching everything to the fuselage will be better.

Not sure, as i am not a seasoned player.

[Vanamonde]

I attach my wings to the hull at a single point and then build the wing from that root part. The reason is that if I need to adjust the center of lift, I can do it by grabbing that single part and moving the entire wing. I do not build many large aircraft, though, so I don't know how advisable that is in terms of structural strength. 

[4x4cheesecake]

So it happened that I was looking through the 'Settings'.cfg' and found an option called 'LOG_JOINT_BREAK_EVENT' which is 'false' by default. I changed it to 'true', grabbed my craft and tested it again.
Well, there is still no entry in the flight protocoll, but there is one in the console/output_log:

Finally, this is a proof for the joint breaking apart which will result in parts crashing into the craft, like @Vanamonde said right from the start

[Gilead]

On your screenshot we can read "Joint broke under the force of 0.00"

That 0.00 is weird, no? It's like saying that the joint broke under no force.

[4x4cheesecake]

1 hour ago, Gilead said:

On your screenshot we can read "Joint broke under the force of 0.00"

That 0.00 is weird, no? It's like saying that the joint broke under no force.

Well, technically this is correct because the joint broke under torque.

or

It is bugged/not finished which would explain why there is no entry in the flight protocoll and you have to edit the settings.cfg to enable the logging. Further, the cheat option 'unbreakable joints' didn't help in the situation, so I assume that this option will override actual forces with 0 but ignores any torque.