Pasting Surfaces

[Pointdump]

Struggling to understand some key concepts, and Helpspeak is my second language.

From the Help Section:
"You cannot paste the grading surface into the surface that you are using as the target surface. This is disallowed because of the dynamic relationship between the gradings and the target surface. To accomplish this task you should create a copy of the target surface and paste the grading surface into the copy."

1. Why do they refer to pasting the grading surface INTO the target surface? Shouldn't one surface be pasted ONTO another? Yes, that bothers me.

2. Why can't you paste a grading surface onto a target surface? I thought "dynamic relationships" was what Civil 3D is all about. How do you make a copy of the target surface?

Dave

[Joe-Bouza]

Hi Dave

I believe pasting "IN' is the vernacular because it is a collection of objects in another object.

An pasting a grading "IN" the arget crteates a circular reference where the grading would continuously look for updates to the target.

That my interpertation.

[AllenJessup]

For 1. Into rather than onto because I would thing that onto would create one Surface on top of another. Into because everything within the bounds of the pasted surface is removed from the target surface and the pasted surface is incorporated into the target.

2 may be because it creates a double dynamic link. Not sure on that one.

Allen Jessup

[Pointdump]

Thanks, Joe and Allen. That gets me a little closer.

"Into because everything within the bounds of the pasted surface is removed from the target surface"

OK, that's something I didn't get when I read the Help Section. That kinda explains the "into". But I still don't get why the target surface needs to be a copy. What's different about a copy? Why would a pasted grading surface create a circular reference with the original target surface?

But beyond that, what is the usefullness of pasting a grading surface? Why not just make the grading group a surface and compare it to the base surface to get volumes? Is pasting necessary to make a grading plan?

Dave

[tcorey]

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@Pointdump wrote:

 Why would a pasted grading surface create a circular reference with the original target surface?

But beyond that, what is the usefullness of pasting a grading surface? Why not just make the grading group a surface and compare it to the base surface to get volumes? Is pasting necessary to make a grading plan?

Dave

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Hi Dave,

1. If you have an OG surface as a target and then paste the FG surface into that, it would be like the gradings targeting themselves.

2. The usefullness of pasting fg into og is to make a surface that is a complete fg for an entire site. Even areas that aren't graded are included in this project-wide surface. This is not something you necessarily need, but it can be useful. You don't need it for calculating volumes.

Your earlier question about how to copy a surface. What I do is make a new blank surface, and then I paste OG into that followed by pasting of FG.

Best regards,

Tim

[AllenJessup]

One reason to past FG into OG and create a finished surface is if you want to render it. Unless you're whole FG is above OF just displaying both surfaces would look line a mess.

Allen

[Pointdump]

Thanks, Tim.

I see now the usefullness of being able to paste one or many grading surfaces into the (copy of) target surface to see the final vision.

I can accept "targeting themselves" as a forbidden operation, but I don't understand it. Not at all.

Your method of copying a surface is interesting, and I'll definitely make a note of that.

Dave

[Pointdump]

Thanks, Allen. I haven't done much with rendering, other than "Oh, Thats Nice," in the tutorials. But I think I see a use for this pasting operation for a Finish Grading using several Grading Surfaces as part of a large editable project. It bears further study.

Dave

[andrewpuller3811]

Pasting surfaces together is especially relevant when you want to view a road or pond in cut.

Without pasting the surfaces together, you will not be able to see the road or pond at all.

[MikeEvansUK]

Don't forget that you may need to add featurelines for the bounding edges of a surface into the final otherwise you get holes.

[Pointdump]

Thanks, Andrew. Looks like I need to spend a day with the Help/Tutorial Section, nailing down some grading concepts. 

Dave

[Pointdump]

Mike,

"Don't forget that you may need to add featurelines for the bounding edges of a surface into the final otherwise you get holes."

That is exactly the sort of thing I need to learn about. If the point of pasting a surface is to see how it plays with the targeted surface, i.e., the existing grade, then why is pasting to the targeted surface not allowed? I'm struggling to understand the work flow of grading, and I don't have a good enough handle on the key concepts to be able to ask the penetrating questions that will allow full understanding to come crashing down.

I stumble on.

Dave

[troma]

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@andrewpuller3811 wrote:

Pasting surfaces together is especially relevant when you want to view a road or pond in cut.

Without pasting the surfaces together, you will not be able to see the road or pond at all.

---

Not totally true.  If you just display contours and TIN lines, you can see through one surface to the one beneath.  It's only when you do 3d visualizations or display elevations etc. that you can't see through a surface.  Even then, you don't necessarily need to paste.  New feature (2013 or 2014?) you can use one surface as a boundary to another: so you make a hole in (a copy of) the OG so you can see your FG.

[troma]

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@Pointdump wrote:

...

If the point of pasting a surface is to see how it plays with the targeted surface, i.e., the existing grade, then why is pasting to the targeted surface not allowed?

...

Dave

---

I think the key is in understanding the dynamic behaviour of all these objects.

Say I have a featureline representing a ditch, and I grade up at 3:1 on both sides targeting the original ground surface.  I can see the side slopes and the extent of grading needed.  Then I get new topo info and I make edits to my original ground surface.  The grading will automatically update and find the new tie-in points where it targets the original ground.

A paste is also a dynamic link.  Say I paste surface A into surface B.  Then I make edits to surface A, adding breaklines for example.  Surface B will also update, or at least be marked out-of-date until you rebuild it.

But what happens if you paste the grading surface into the OG surface?   So now you have a grading, that is making a surface, that is pasted into a surface which it is also targeting.  Essentially it is targeting itself.  This is your circular reference.  The grading is saying to itself "So I'm meant to keep going up at this slope until I intersect myself, right?"
So the better way is to make the pasted copy of OG, and paste the grading surface into that.  This way the grading know where to stop (it is targeting the good old original ground) but you still get to make a composite surface showing how OG and FG look together.

[Pointdump]

Troma,

Sorry, I'm just not getting it. Why would an updated OG (Original Ground?) surface target itself?

Dave

[troma]

IF the grading is targeting OG,
& IF the grading is creating an automatic grading surface,
& IF you paste that surface into OG;
THEN the grading is targeting the same surface it is creating.

[Pointdump]

Troma,

OK, I can see if a pond grading is pasted into a proposed finish grading, there might be some circularity of reference. But an Existing Ground Surface isn't targeting anything. I'm hopelessly confused, but I appreciate your attempt to explain. Thank you.

Dave

[troma]

Sorry, I can't let it drop!

At the start the Existing Ground Surface isn't targeting anything.

But if you paste the grading surface into the Existing Ground Surface, then yes, the Existing Ground Surface is targeting something. It is now trying to target itself.

(That is, IF you target the existing ground surface with the grading surface.)

Remember, when you paste, you still have a link. So you are setting up a situation where:

the Grading will automatically update as per the Existing Ground;

the grading surface will automatically update as per the Grading;

the Existing ground will automatically update as per the grading surface;

the Grading will automatically update as per the Existing Ground;

the grading surface will automatically update as per the Grading;

the Existing ground will automatically update as per the grading surface;

the Grading will automatically update as per the Existing Ground;

the grading surface will automatically update as per the Grading;

the Existing ground will automatically update as per the grading surface;

the Grading will automatically update as per the Existing Ground;

the grading surface will automatically update as per the Grading;

the Existing ground will automatically update as per the grading surface;

the Grading will automatically update as per the Existing Ground;

the grading surface will automatically update as per the Grading;

the Existing ground will automatically update as per the grading surface...

[Joe-Bouza]

"Dave, you have crystalized my thoughts eloquently" to borrow a phrase.
Notice the never ending Loop you are describing in your last paragraph. Therein lies the defugalty - it created an enviroment for a never ending loop.

[Pointdump]

Troma,

Can I borrow some of your tenacity? I still don't understand, but I'll read and re-read your posts over and over until I do.

So, if I can't paste a grading into the Existing Ground Surface, why is it OK with a COPY of the Existing Ground Surface?

Dave