If you not want explosion on attach piston you can fix the moving part with Merge block. This way you make single grid and Piston is unable to explode top part if you run attach script on that piston. After piston is attached you simply disable merge blocks render piston able to move.

If you connect the main mesh with the sub mesh through a piston, they do not become one mesh. If you connect a grid with a sub-grid through a piston on the head of which a Merge block is installed, then they still do not become one grid. In other words, if you install a cockpit on a piston, even through a Merge block, then you cannot control the ship from this cockpit. This is the problem. A similar thing happens with hinges. You cannot fasten two hinges with two meshes so that they both work in place (like two hinges in a door, you can only have one.) That’s why I asked about the script or mod, I don’t understand programming.

Hi, I never use Scripts but I know a lot use those to control wheels and thruster from subgrid and may be what you need :

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1445055239
Also thrusters :
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=757123653

Could you mount the piston body on a third subgrid, pushing the two subgrids you want to join together at the merge blocks?

Oh! He is talking about how to merge blocks ??

Garsum,
you should share some Steam screenshots of what you want to do, that will surely help to understand what you mean exactly.

https://steamhost.cn/steamcommunity_com/profiles/76561198114521068/screenshot/2367273575930553565/

https://steamhost.cn/steamcommunity_com/profiles/76561198114521068/screenshot/2367273575930553342/

Thanks Dan2D3D. I'm bad at explaining. There is no way to control the ship from the cockpit.

That is very normal because we can't control the ship when the cockpit is a "Sub-Grid", the cockpit must be placed on the same grid where Thrusters or Wheels are to be able to control.

BUT
-> You may learn how to use the Script I have shared, those are especially made for your sub-grid creation.

thanks, I'll try

Info +

What is a "Sub-Grid" :

1 - All blocks placed on Piston head.

2 - Blocks placed on Rotor head.

3 - Blocks placed on Hinge.

=
Those setups create a "Sub-Grid" and we can't control Thrusters, Gyroscopes and Wheels this way.

Well you could add a Remote Control block and antenna block on the Grid where the Thrusters and Gyros are and control the ship from the RC block.