error with spline and pwr_blend tool

[rudo_fr]

Hello,

i notice sometime this spline problem with pwr_blend tool:

when i draw new pwr_sketch spline, it's clean spline with no operator parameters. i clone my spline and use pwr_blend tool to made my object. there is no problem. but if i decide to undo operation just before pwr_blend operation or extract spline from my object, i can't obtain same result because there is pwr_blend tool error (that build nul box).

After analyse splines from object extraction or undo, i noticed there is new operator parameters on my splines: 0)Deriv_Surf:Deriv Surface

This spline modification come only with pwr_blend tool not with pwr_skin tool or other tool operation.
To resolve this pwr_blend problem and remove 0)Deriv_Surf:Deriv Surface on my original pwr_sketch spline, i have to edit edges, select segment and extracte Sel in Edit Edges.....

Did you notice this problem ?
tell me if you need 3dsmax's file, i can send you.

Thanks and sorry for my english.

Rudo_fr

[PiXeL_MoNKeY]

The sub-operator is created as soon as you pick the Sketch for the Pwr_Blend. To verify create your Sketches, create a Pwr_Blend from the Sketches, access the Sketch from inside the Pwr_Blend, expand the Operator Parameters, see that the Deriv_Surf sub-operator has been created. Other ways that it gets created is if you convert a Pwr_CmpSkt or Pwr_Sketch to a Pwr_EditSkt.

Edit: I know what creates it now, it is the creation of the Tangency for the Sketch. By default Sketches have no Tangency. If you create a sketch and the change the tangency from "No Tangency" to "Parallel to Vector" you will get the same sub-object. I believe you only see this with Pwr_Blend, because it is one of the few Objects that bases its default surface off the tangency from the sketches. So by adding a Sketch to a Pwr_Blend object the tangency is created, however the tangency creation isn't undone. The only way to get rid of the object is set your Tangency to none, select the object, set the Sub-Object Editing to remove and extract it. This will create an empty object in your scene that won't be visible.

-Eric

[rudo_fr]

Hello Eric,
ok i well understand your explanation about tangency, thanks again for your reactivity, it's not the first time i have this problem after make undo and try to rebuild model with other tool. Now i well understand how i can check my original curves construction.

Thanks a lot Eric,

Sorry for my english,

Rudo_fr.