What happens to sketches?

Nick Van Laar

What happens to a sketch after it is consumed by a 3D object?  How do I go back and edit the parametrics after creating a solid?

Thanks,

Nick

Scott McKenzie

As far as I know, once a sketch, or polyline is extruded, there is no going back to edit the sketch...

Joe Dunfee

Many years ago, I recall that there was some sort of variable in AutoCAD that caused AutoCAD to retain the polyline.  But, I had not been able to re-discover that variable. Your message prompted me to look again.

I finally found it.  The variable is DELOBJ.  a 1 will cause the objects to be deleted.  There are other values that will cause them to be retained or to prompt you. Search for DELOBJ in the settings dialog box.

-Joe

Nick Van Laar

So Bricscad is not a true parametric modeler in the same sense as Geomagic,  Inventor, or Solidworks... The Bricscad parametric modeling hype is a little over-sold.

Scott McKenzie

Interesting, I didn't realize that there was a variable to retain the entities used to create solids.  Just thinking about this, I tried to create a rectangle, constrain it with dimensions, extrude it with DELOBJ set to 0 (the rectangle and constraints remain), changing the dimension value of the constraint has no effect on the solid.  Could it be possible to redefine the extrude and 3D object creation commands so that the new solid is created with a bit of xdata linking the solid to the source objects.  When a user changes a source object a command is sent to delete and rebuild the solids which contain xdata matching an entity name of the modified source?  I would imagine it could be done, but at first thought it sounds like a lot of commands would need to be redefined to make it work...

Roy Klein Gebbinck

@ Nick: The Platinum version has 3D Constraints. Have you already looked into that?

Nick Van Laar

@Roy Klein Gebbinck:

@ Nick: The Platinum version has 3D Constraints. Have you already looked into that?

That is what I am demo-ing.  They are OK, but does not make Bricscad parametric like the above mentioned programs are parametric.  When I think parametric, I think history-based modeling and the ability to use existing constraints to drive other constraints.  I am still liking Bricscad, except I do like the ribbon in ACAD (way more screen real-estate) and the parametrics are over-sold IMHO. 

Joe Dunfee

 The word "Parametric" has a history from before programs like SolidWorks came along.  So, BricsCAD is a true parametric program, just not as full-featured as some of the other programs you mentioned.  Though, like you, I do think it is a bit oversold.

-Joe