Radial Symmetry Space Button not working

[JohannesMP]

Overview

When in the editor (VAB or SPH), and placing a part with radial symmetry enbled you have access to the Radial Symmetry Space Option, which is supposed to let you switch between having the symmetry mode be relative to the vessel, or relative to the parent part.

It appears that while this option has a hotkey, as well as an on-screen button, its toggle state does not actually currently affect object placement; The part placement always defaults to using the vessel as the axis of symmetry and not the parent part.

 

Details

Given this simple vessel which has two tanks (FL-T400 Fuel Tank) on radial decouplers attached to a larger central tank (FL-T800 Fuel Tank) using 2x symmetry:

The default behavior for attaching a small spherical tank is to do so relative to the vessel. In other words, The spherical tank is placed with the axis of rotation being through the center of the vessel:

 

In the tools section there is an Option that toggles between "Vessel" (Default) and "Parent"

Which when pressed displays the corresponding notification:

This option can also be toggled by hitting the F hotkey, described on the Key bindings wiki page as "In place mode: Toggle Symmetry between vessel or parent part".

 

With it set to "Parent Part", I would expect the spherical tank to now be mirrored relative to is parent part (the FL-T400 Fuel Tank), which would look like this:

 

However this is not currently the case. The above image was mocked up using single symmetry, and was not achieved using the "Parent Part" setting.

Here is a gif screen capture showing the issue: https://imgur.com/p0jLF0y

Note how despite being in 'Parent' mode and the on-screen notification saying "Radial Symmetry around Parent Part", the spherical tank is not mirrored around its parent part, the FL-T400 Fuel Tank, and is instead always mirrored around the vessel's center part, the FLT-800 Fuel tank.

 

Summary

Am I correct in my assumption that when the Radial Symmetry Space Option is set to "Parent Part" that objects should be placed in relation to their parent part, and not the vessel? If not, I would really like to know what this option is intended to do otherwise.

 

Tested using KSP 1.4.5.2243 (WindowsPlayer x64) en-us

 

Note: If an admin could move this topic to the Technical Support (PC, unmodded installs) forum, it would be much appreciated.

Edited August 7, 2018 by JohannesMP
formatting

[Rocket In My Pocket]

I noticed this as well a few days ago but brushed it off as me being an idiot and not remembering how things worked.

Would be interested to know if this is indeed a bug.

Btw, very well documented with the pictures! You should have been a lawyer. 

Edited August 7, 2018 by Rocket In My Pocket

[Superfluous J]

Holy cow would you believe I have never, ever noticed that button? I have worked out all manor of ways to achieve what I want (usually involving detaching the side part, attaching it inline, putting the radial thing on it, and then reattaching the main part back to the side of the ship) and have never figured out how or why the game sometimes chooses to radialy attach across the part or the ship.

Now I know it's because I hit F by accident.

Where's that "mind blown" gif?

[4x4cheesecake]

I know this button for quiet some time but never thought about the actual use of it since nothing changes when switching between the modes and I forgot about the button again (even though I use the  'F' key everytime to switch between local and absolut mode when using the move or rotate tool). Now I read this post and I'm pretty sure you found a bug in an editor feature which is unknown for many people. I did some tests as well and there is actually a way to use this feature but only with x2 symmetry. Just grab the part you want to attach, switch to 'parent' mode, press 'X' to increase the symmetry count and now you are able to place the part in symmetry around the parent part (but, as mentioned before, just x2 symmetry is possible). Also, as soon as you pick up the part, it switches back to use the vessel axis even though the 'parent' mode is still active:

 

[OHara]

When I started with KSP I thought "symmetry around parent/vessel" meant where to hang the N new parts: N attached to one parent, or 1 attached to each of N symmetrically-related parents.  

But for me, KSP enforces the rule
"if parts are attached to a parent that has symmetry about a grandparent, the attached parts have the same symmetry to the same grandparent."
(That is, I had not figured out how to do what 4x4cheesecake did.)

It seems "symmetry around parent/vessel" gives us only the choice: when we attach N parts radially to a single parent, about which axis should they be arranged, that of the parent or that of the vessel?  This is rarely useful (but the option doesn't get in the way so I have no complaints.)

Edited August 8, 2018 by OHara
more sensible image size

[JohannesMP]

Thanks @4x4cheesecake and @OHara, that does clarify some things.

As far as I understand it now, you will only see a difference with the Parent and Vessel options if your parent part is not inline AND not attached with symmetry.

 

What the Vessel/Parent Symmetry Setting Actually does

Given this vessel:

 

Attaching a part to the non-inline part in 3x symmetry with Vessel symmetry results in this:

The parts are mirrored as if around the root of the vessel axis, but positioned over the parent part.

 

And attaching a part to the non-inline part in 3x symmetry with Part symmetry results in this:

The parts are mirrored around the parent part's axis.

 

Note that this no longer works if the parent part you are attaching to is itself symmetrically attached. Then all attachments to it will behave the same way they do with the Parent option selected on a non-mirrored parent part.

 

Here is a video showing the above details: 

 

 

As shown in the video posted by @4x4cheesecake, if you are attaching a part to another 2x symmetry part, hitting the symmetry hotkey (X) will perform the behavior I was originally expecting. Sort of...

 

What hitting X in 2x symmetry does

You have to use the hotkey while mousing over the part, because the behavior disappears once you mouse off the parent, so clicking the symmetry UI button is not an option.

However even more interesting, if you hit X to enable this local symmetry, now hitting F will actually do something again. This results in 3 possible ways to attach a child to a 2x parent symmetry:

1. Default: radially around vessel axis, one on each parent part
   
   
   After hitting F:
    
2. In Parent mode: The part is mirrored around the parent part axis, on one side only
   
    
3. In Vessel mode: The part is mirrored around the vessel axis, but translated onto the parent part:
   
    

Once again it should be noted that 2 and 3 above only work if you hit X while the parent part is in 1x or 2x symmetry.

 

Whew, ok, I think that covers it?

 

 

 

 

Edited August 8, 2018 by JohannesMP