Hi…

Is there no way of selecting an object and align the CPlane to it?

And how about selecting a bonechain and changing its alignment so that x points up???

s7r83dg3
Is there no way of selecting an object and align the CPlane to it?

Tab - construction plane tool
Then select three points on your object
The construction plane should now snap to those three points.

The first selection determines any point on the plane, the next two selections form the origin and direction of the construction plane.

Note: Hit enter after first selection simply translates the Construction plane origin to that point maintaining it's orientation
Note: Hit Enter after the second selection will re-orient the Construction plane only.

Tip: You can enable the Viewport Memory toolbar and save your construction planes for re-use later on.

s7r83dg3
And how about selecting a bonechain and changing its alignment so that x points up???

Bones aren't joints. In general, the setups in Maya don't quite translate in to Houdini wrt some of the things you hang off joints to build Animator widgets. Good thing is that most of the Maya set-ups aren't required to get good rigs in Houdini going.

You can always insert a null in to the bone chain if you need to hang stuff off of an end of a bone joint.
Just place a null between the bones. Create a channel reference from the Bone Length parameter of the parent to the tz Translate Z channel in the Null and negate it.

If I want to hang controls off of a bone chain, I will hang a null off the joint in question, put in a -ch() in the tz channel referencing the bone's Length parameter.
Then parent a Blend Object off of that Null and check off the Rotate buttons so as not to inherit any rotates from the bone chain but from the world.

You can wire in a second object (usually a null) in to the Blend Object and use that second null's rotate parameters and/or scale parameters. Maya users know this as one form of Constraints. This is one of many different ways of creating constraints in Houdini.
You can wire in as many objects in to the Blend Object and create complex constraints quite easily.

See the attached hip file for a simple setup


Now what about rotating bones in Houdini?
Well when you rotate a bone in Houdini, it determines how the rest pose of the bones is altered. Believe it or not our IK solver actually will tolerate animated IK Rest positions. You may have to increase the solver tolerance in the IK CHOP but that is real handy to know.

The way you go about re-setting the rest pose of a bone is to first in the Main Menu Edit > Objects > IK Rest
will display all the bones at their Rest Position
Turn on the IK Critical Zone option in the Display Options dialog (hit “d” in viewport to get at them).
Now you can rotate the bones and you can see that this determines the placement of the IK Critical Zone.
Now turn off the IK Rest option and you can see that the IK Critical Zone as been re-set.

Again, rotating bones in Houdini is different than rotating Joints.

old_school

s7r83dg3
Is there no way of selecting an object and align the CPlane to it?

Tab - construction plane tool
Then select three points on your object
The construction plane should now snap to those three points.

The first selection determines any point on the plane, the next two selections form the origin and direction of the construction plane.

Note: Hit enter after first selection simply translates the Construction plane origin to that point maintaining it's orientation
Note: Hit Enter after the second selection will re-orient the Construction plane only.

Tip: You can enable the Viewport Memory toolbar and save your construction planes for re-use later on.

…

Hello;

I tried these steps without success:

1) I clicked on C_PLane button.
2) Then I selected tree points on my geometry
3) I hitted the enter.

C-Plane was orientation picking updated recently.

To use a three-point pick:

1. enter c-plane orientation picking mode: hit ‘/’
   
2. right click the c-plane and select ‘use extended mode’
   
3. click three points