Infill Grading VS Feature Line Grading

[Anonymous]

Hello,

AutoCAD help says:

"An infill grading has no criteria applied to it. Any area bounded by feature lines or lot lines that is not already a grading can be converted to an infill grading."

So given an area enclosed by a feature line, an infill grading can be created. Using the same features line, an feature line grading can also be created.

I just wonder what is the difference between these two surfaces? They both have no criteria applied to them.

Thanks,

Xiangyu

[Neilw_05]

When you apply a grading to a feature line, C3D automatically applies an infill between the parent featureline and the one created by the grading. When you look at the grading in a 3D view with a shading style applied you see the infill. Consider the case where you have a building pad and you apply a grading to the perimeter that targets the existing ground. If you look at the grading and the pad featureline in a 3D view you'll see the gradings have infills but the pad does not. Also if you set the Create Surface option in the grading group settings you'll also see the resulting surface does not include area inside the pad.

There are 2 ways to remedy that hole in the surface:

1: Add the building pad featureline to the surface as a breakline which causes the surface to triangulate across the open area.

2: Add an infill inside the building pad featureline to add that area to the grading.

Does it matter which approach you use? For the most part, no. You can get the same results either way for surface models and cut/fill volumes . But there are advantages to using infills, namely:

1) The gradings won't have holes when viewed in 3D

2) Any additional gradings that may project onto the pad will intersect the infill.

3) You can use the earthwork balance tool to automatically adjust the gradings to achieve balanced quantities.

[neilyj666]

But also remember gradings can be problematic and cause issues with the drawing i.e. crashes/corruption

[Joe-Bouza]

Projection grading are dynamic. Infills are static

[Anonymous]

excuse me but are you sure?

I'm running c3d 2013 and I tried editing a closed fline with an infill applied and the grading reshapes automatically

[Joe-Bouza]

Pardon me; I often think everyone is in my head when a say something.

In some cases they cant react to changes. for example lets say you use a projection grading by distance and grade and tie that to an infill via connecting the projection line with your infill area. Change the projection distance and the infill is gone. (not dynamic)

[Neilw_05]

The infills are dynamic to any changes to the perimeter of the enclosed area. If something causes the area to become open, the infill disappears.

[Joe-Bouza]

See what I mean! I thought thats what I said 🙂

Bill has been after me for years for that. My own little language I guess

[Neilw_05]

I guess my point was: once the area becomes open the infill ceases to exist. Therefore there is no such thing as a static infill.

I'm sure you knew that but it didn't come out that way.

[Joe-Bouza]

Psych!
I was just bustin. But think of this case: you create a pad with a 2% cross pitch with an infill and then you go back and want it to be 3%. Dependinging on the complexity of the pad - its not all that dynamic, no?

[Neilw_05]

Well if you adjust the perimeter of the pad to be 3%, the infill will warp to fit. Is that not how you understand infills to work?

[Joe-Bouza]

The point is, in a projection grading if I adjust the parent FL the projection reacts. If I adjust the criterior of the projection grading everything adjust.

To adjust an infill you have to work at it with various tools and, at times, some brain power.

To me that makes an infill less dynamic than a projection grading. I know the infill warps to "user" intervention, but the key word is intervention. The infill is as dynamic as the feature lines it is bound by. Thats all.

Don't get me wrong Neil I think infills are essential.

And by definition all an infill does is tell the grading its ok to triangulate across me.

[Neilw_05]

"And by definition all an infill does is tell the grading its ok to triangulate across me."

That's exactly all it does. You can't manipulate them but they are always dynamic to changes. I guess I don't understand your definition of dynamic but I think it is now clear to everyone what they do.

[Joe-Bouza]

You think so.

¹dy·nam·ic

adjective \dī-ˈna-mik\

: always active or changing

: having or showing a lot of energy

: of or relating to energy, motion, or physical force

CloseStyle: MLA APA Chicago

Full Definition of DYNAMIC

1

   also  dy·nam·i·cal \-mi-kəl\ a:  of or relating to physical force or energy b:  of or relating to dynamics (see dynamics)

2

a:  marked by usually continuous and productive activity or change <a dynamic city> b:  energetic, forceful <a dynamic personality>

3

of random-access memory:  requiring periodic refreshment of charge in order to retain data

Neil, are two Feature lines drawn in space Dynamic? No. The surface they are assigned to is. If two feature lines adjacent to one another and the one on the left is used to project a 2% slope to the one on the right, with the projecting elevation tool - are they dynamic, if I change one elevation of the FL on the left? No, but the surface they are assigned to is.

So how does the presence of an infill between the two suddenly make these objects dynamic?

The surface the infill is assigned to is dynamic not the infill.

Thats how I define it.

Of course if you consider any changes that ignore the original criterior and/ or intent to be represented in your finished product then yes Infills are dynamic.

[Neilw_05]

I certainly did not mean to imply an infill makes the feature lines around it dynamic to it in some way.

If you look back at e.topo's reply (5th in the thread), he took exception to your comment about infills being static by noting that an infill expands or contracts dynamically when the enclosed area changes.

That is my perspective as well. I think we can all agree on that.

[Anonymous]

Thank you very much for the reply!

Xiangyu

[HHasbrouck]

Dear NeilW,

Are you still answering questions regarding this topic?  I have a simlar problem - but I am not dealing with a building - I have a simple sloping plane.  I have used the closed feature line as a breakline (image1)

Then I greating a projection grading to the slope using '3to1 to slope'as the criteria

the contour disappears as does the surface.  within the simple 2% plane.  Can you advise me on how to have the slide slopes as well and the contour within the interior be united in the same surface rather than creating a seperate surface for the simple plane?

In the end - I created two surfaces and pasted the sloped plane into the side slopes.  I though this was a bit inelegant and was searching for an alternative.

thank you and i apologize for the 'beginner' level question

Hope

[Neilw_05]

This is exactly the situation I described earlier with regard to the building pad having a hole in it. What you need to do is apply an Infill within the enclosed area. Then you will see the interior is included in the grading and the contours will show in the resulting surface.

[jmayo-EE]

I think that's also the 'gradings can be problematic' issue even though that's just a small part of the problems that may or may not appear...

[Joe-Bouza]

One thing I have come to grips with, is that Infills do not like to be associated with Dynamic featurelines; grading dissapear and must run audit purge for every grading operation. which dovetails into my hair-splitting symantics debate over the definition of "Dynamic"... editing a grading is not quite as dynamic as editing an object driving the grading. IMVHO