Gradings are wonderful things.  Problematic as they may be, they have been quite useful, even back in LDD.  The new Gradings have a host of settings and features that carry with them new terminology that is sometimes confusing.

In light of studying preparing for the Grading Lab I will assist with, I thought it would be nice to explain some of the terms that are often hard for new users to get a grasp of.  It’s not that they are inappropriate, but they all start to sound the same to a new guy.

Gradings, Grading criteria, Grading Criteria Sets, Grading Groups…..  See what I mean?  Today we’ll take a brief tour of these terms.


 Grading – This is a 3D object that all the fuss is about. 

This It is built on a frame of feature lines (rough interpretation) and autonomously projects its own set of faces, based on instructions that it was assigned.  This instruction set known as a Grading Criteria, is stored within the Grading object, allowing the object to follow it’s instruction no matter what changes to its environment occur.  Objects created by Gradings can be as simple as a single Grading building pad, or complex grade scenarios, such as a littoral shelf detention pond, that might contain numerous Gradings.

 Grading Style – The style applied to the Grading that controls its appearance.

This can be found in the Grading section of the Toolspace Settings Tab.

Grading Criteria – The list of instructions that the Grading object must follow.


These are stored in a Grading Criteria Set, in the Settings Tab of the Toolspace. Each Grading contains 1 grading criteria, that tells the Grading how to act.  Should it project to a surface, or over a specified distance at a given slope?  The list of possibilities goes on and on.  If the root Feature line is adjusted or the target surface changed, the Grading continues to follow the instructions in its Grading criteria, and dynamically re-grades itself.

Grading Criteria Set – this is simply a collection of grading criteria.

An organization tool, that becomes a filter when creating a Grading.


Gradng Group – A Grading Group is the collection of Gradings that mold together into a single FG graded object. 

I think this doesn’t get explained thoroughly.  We usually just figure it out.  One of the nice things (there are a few) is that all the objects in that group automatically work together to create the final product.  That littoral shelf detention pond might be the name and focus of the Grading Group.  The end product of the group could be a volume surface, that is the product of all the Gradings that went into that particular grading group, and is automatically updated as new Gradings are created.  It helps the system understand and collect instructions into a logical outcome.

Making the Grade Lab at AU

Check out the Lab “Making the Grade” taught by Ron Couillard.  It will be at CV118-6L  Tuesday 03:00pm – 04:30pm PST  MB Ballroom K (Lab)

CV204-1L Wednesday 08:00am – 09:30am PST MB Ballroom H (Lab)
It looks like it will be a pretty good class.

He’ll go through the settings and explore a few scenarios along the way.