MFnAttributes and Maya's new Node Editor

[alexander-sknarin]

Hello, I'm trying to make my c++ written nodes look accurately in Maya's new (since 2012) Node Editor.
My plugin presumes that it's nodes will be often connected/reconnected so I want to expose only necessary connections of each node to an artist.
Maya's Node Editor has three display states for node - "hide attributes", "show only connected" and "show primary attributes". For purposes of my plugin I want to control what to show on my nodes in "show primary attributes".

1. Is it there any explicit way to add attribute to "primary attributes"? For example if I have typed attribute for input mesh. It's connection always become hidden on Node until I push RMB on node and select "Show All Attributes".
   Only way to make it visible in "show primary attributes" mode i found is to tAttr.setKeyable(true). But it isn't looks like correct way to do this ((.

2. How to hide output connection on attribute?
   When I "tAttr.setWritable(false)" all works as expected (connection on left side of node dissapeared), but with "tAttr.setReadable(false)" connection on right side of node still exist:
    
   As this example shows standart Maya's nodes manage to do it somehow.

3. Is it possible to control order of attribute appearance?
   For example attributes on my node on picture above appeared in completely different order than they were added in initialize section of my plugin.

thanks in advance.

[k-schubert]

Hi, 

+1

have a simliar problem of not being  able to control which pins (input/output) appear in the node editor (maya 2016)

Works kinda for static attributes, but for dynamics, only setHidden() has an effect, readable and writable seem broken...

Best,
Kai