Method for grading between two irregular pads???

[ConnieB]

Hey guys and gals, I need a tip!

I have several irregularly shaped building pads which are likely to change shape and/or elevation.
These pads are connected to each other by a side slope which needs to be 2:1.

What's the best way to grade these so that when I move the pads, the slope and it's daylight line recalculates itself? For example, top slope from one pad would hold, slope would hold, and daylight needs to move.

I'm experimenting doing this with feature lines and grading objects, but I'm not sure if I'm heading in the right direction.

non-automatic way, I could do this by making the op a feature line, make the bottom pad a surface, and then create a daylight grading object into the lower pad.... I'm looking for a better/more automatic way.

Also, if there's more automatic way, could I make it recalculate the area of the changed pad?
Any thoughts or input would be appreciated!!! Edited by: ConnieB on Sep 26, 2008 6:05 PM

[Anonymous]

Use a corridor.

--

Lance White
CAD Manager

HP 4600 4 GB Ram
Intel Core 2 Duo 2.66
ATI FireGL V5600
(8.391.2.1100)
Windows XP PRO (SP 3)
2008; (All SP) LDT, MAP 3D
2009;
Civil 3d 2009 Update 1 Version 2, Map 3D, Raster

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"ConnieB" wrote in message
href="news:6039791@discussion.autodesk.com">news:6039791@discussion.autodesk.com...

Hey
guys and gals, I need a tip! I have several irregularly shaped building pads
which are likely to change shape and/or elevation. These pads are connected to
each other by a side slope which needs to be 2:1. What's the best way to grade
these so that when I move the pads, the slope and it's daylight line
recalculates itself? For example, top slope from one pad would hold, slope
would hold, and daylight needs to move. I'm experimenting doing this with
feature lines and grading objects, but I'm not sure if I'm heading in the
right direction. non-automatic way, I could do this by making the op a feature
line, make the bottom pad a surface, and then create a daylight grading object
into the lower pad.... I'm looking for a better/more automatic way. Also, if
there's more automatic way, could I make it recalculate the area of the
changed pad? Any thoughts or input would be appreciated!!! Edited by: ConnieB
on Sep 26, 2008 6:05 PM

[ConnieB]

Isn't there a way to do this using grading objects?

[ConnieB]

Is anyojne using Civil 3D for creating a rough grading for a site of some 40-50 acres???

I can't seem to use much in a way of grading objects to work with pad grading - before it crashes.

Do most people turn the pad outline into an alignment, then daylight into a pad next door using a 2:1 from an assembly?

Seems like I should be able to create a grading group for slopes, and go 2:1 from one pad into another???

I was able to create a pad outline as features, and created a lower pad with a feature, and an infill (with a surface). After that I used a grading object to go from upper pad intop the lower pad and daylight into the infill surface. Worked okay on a small area.

After this, any time I need to make a revision to one of the involved elements, my drawing creashes, and I make no headway past this. Revision may be a change in the upper pad feature elevation or a horizontal position.

[Anonymous]

I think this may be a minority opinion, but here
goes, anyway.  (By the way, I think rough grading for 40-50 acre sites is
one of the tasks in which Civil3D shines very brightly...........at least it
does for me.)

I think over use of gradings is where most people
find themselves horribly frustrated and distracted into thinking about the
software instead of their design.  Something in one of your posts mentioned
daylighting from one pad to the other.  If necessary, create a temporary
surface (out of objects which define your pad to be daylighted to), then use a
grading to find where that would be.  At that point, explode the grading by
the daylight portion, which will leave you a 3dPoly, defining that line. 
Weed it, add to your surface as a breakline and move on.  When a change
happens, erase the 3dPoly and do it again.

I often see folks fiddling with grading and asking
the type of questions you've posed when a couple of polylines (added to a
surface as breakline or contour data) do the trick just as well, and sometimes
better.

All the automation is cool, but the associated (and
inerent) problems tend to negate the benefit, if you rely too heavily on
it.

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<ConnieB> wrote in message
href="news:6039920@discussion.autodesk.com">news:6039920@discussion.autodesk.com...

Is
anyojne using Civil 3D for creating a rough grading for a site of some 40-50
acres??? I can't seem to use much in a way of grading objects to work with pad
grading - before it crashes. Do most people turn the pad outline into an
alignment, then daylight into a pad next door using a 2:1 from an assembly?
Seems like I should be able to create a grading group for slopes, and go 2:1
from one pad into another??? I was able to create a pad outline as features,
and created a lower pad with a feature, and an infill (with a surface). After
that I used a grading object to go from upper pad intop the lower pad and
daylight into the infill surface. Worked okay on a small area. After this, any
time I need to make a revision to one of the involved elements, my drawing
creashes, and I make no headway past this. Revision may be a change in the
upper pad feature elevation or a horizontal position.

[Anonymous]

Grading to  temp surfaces is one approach. You
can also just use an elevation target for grading from one pad to another,
but If the pad elevations change you would have to manually adjust the targets.
One approach requires more set up while the other requires more work to
edit.

"TomD" <
href="mailto:tdivittis@comcast.net">tdivittis@comcast.net> wrote in
message
href="news:6040128@discussion.autodesk.com">news:6040128@discussion.autodesk.com...

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I think this may be a minority opinion, but here
goes, anyway.  (By the way, I think rough grading for 40-50 acre sites is
one of the tasks in which Civil3D shines very brightly...........at least it
does for me.)

I think over use of gradings is where most people
find themselves horribly frustrated and distracted into thinking about the
software instead of their design.  Something in one of your posts
mentioned daylighting from one pad to the other.  If necessary, create a
temporary surface (out of objects which define your pad to be daylighted to),
then use a grading to find where that would be.  At that point, explode
the grading by the daylight portion, which will leave you a 3dPoly, defining
that line.  Weed it, add to your surface as a breakline and move
on.  When a change happens, erase the 3dPoly and do it
again.

I often see folks fiddling with grading and
asking the type of questions you've posed when a couple of polylines (added to
a surface as breakline or contour data) do the trick just as well, and
sometimes better.

All the automation is cool, but the associated
(and inerent) problems tend to negate the benefit, if you rely too heavily on
it.

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<ConnieB> wrote in message
href="news:6039920@discussion.autodesk.com">news:6039920@discussion.autodesk.com...

Is
anyojne using Civil 3D for creating a rough grading for a site of some 40-50
acres??? I can't seem to use much in a way of grading objects to work with
pad grading - before it crashes. Do most people turn the pad outline into an
alignment, then daylight into a pad next door using a 2:1 from an assembly?
Seems like I should be able to create a grading group for slopes, and go 2:1
from one pad into another??? I was able to create a pad outline as features,
and created a lower pad with a feature, and an infill (with a surface).
After that I used a grading object to go from upper pad intop the lower pad
and daylight into the infill surface. Worked okay on a small area. After
this, any time I need to make a revision to one of the involved elements, my
drawing creashes, and I make no headway past this. Revision may be a change
in the upper pad feature elevation or a horizontal
position.

[Anonymous]

Maybe but since you pretty much have to explode a
grading object to really use it I don't like them much.

--

Lance White
CAD Manager

HP 4600 4 GB Ram
Intel Core 2 Duo 2.66
ATI FireGL V5600
(8.391.2.1100)
Windows XP PRO (SP 3)
2008; (All SP) LDT, MAP 3D
2009;
Civil 3d 2009 Update 1 Version 2, Map 3D, Raster

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"ConnieB" wrote in message
title="news:6039856@discussion.autodesk.com CTRL + Click to follow link"
href="news:6039856@di......

Isn't
there a way to do this using grading objects?

[ConnieB]

Hey guys, Thanks a bunch for the feedback 🙂
Sounds pretty close to what I've been doing. I've been calling it the Semi-automatic method.

There's been a recent push with this particular client to turn tings completely automatic - so that when you move a feature with infill, say 5 feet up, the grading element updates itself. In my experience, while that's possible on paper with few elements, it doesn't work well on a site with 10 superpads.

My civil 3D always crashes and burns when i try this - but I thought I'd ask, and see if maybe there's a better way then what I've been doing. Sounds like we're not quite there yet with C3D.

Thanks a bunch for the feedback guys 🙂

[ConnieB]

"Grading to temp surfaces is one approach. You can also just use an elevation target for grading from one pad to another, but If the pad elevations change you would have to manually adjust the targets. One approach requires more set up while the other requires more work to edit."

Oh, as a point of information, just thought I'd mention that usually grading to elevation doesn't cut it in this case, because theese large pads are not flat. They usually drain at 1% or 2%, so across one or two acre pad, I could have as much as 10' change of elevation from one end to the other.

This method works rather good for smaller pads 🙂

Anyway, thanks again for the help 🙂

[darkman257]

Hey Neilw -

You and Sinc responded to my stacked feature lines.  I resorted to making separate sites.  Eventually I will get to asking how to take the stacked feature lines and their associated gradings and put the two volumes together.  (think of a clam shell, nearly identical halfs that are closed.  You have top contours, bottom contours and the void in the middle).  But to my question of the evening...

I have essentially two rectangular pads, one at elevation 1007 and the other at 1002. I would like to do a cut and fill at a 4:1 slope for both pads but more importantly I would like to have an even grade from the top rectangle to the lower rectangle as much as possible.  I have seen you discuss this by creating a intermediate surface.  I really don't follow at this time.  However, what I was thinking to do was to offset the feature lines on both pads and then connect the offsets to make like a ramp/grade to the bottom pad.  However, how would I make the feature lines have elevations to match the grade as you go down the "ramp" so to speak. That is if I offset both pads the offsets will be at the elevations of the offsets, how can any connecting feature line from the top offset to the lower offset take the designated slope or actual slope between the two offsets?

I have attached a picture of the two pads.  I looked at the tutorial for grading two pads but the feature line was essentially created and was not part of the lesson more of just cleaning up and grading/infilling not how to really link the two.  Thanks!

[Neilw_05]

I may not understand your objective correctly, but it sounds like you want the pads to daylight at 4:1 around their perimeters, but you want a straight grade from one pad to the other where they share common sides.

If this is correct you would be better off building one surface from the 2 pads. To do this, create a feature line that surrounds the outer perimeter of the 2 pads. This feaureline will define the elevations and outline of both pads except for the region between them. Apply a grading to daylight at 4:1 from this perimeter feature line and build a surface from the grading. Next, add a feature line across the open edge of each pad and add them as breaklines to the surface. By adding these breaklines to the surface you will force the surface to triangulate between the pads. Lastly add infills to the pads to close the open areas.

I'll follow up with a file or screen capture to illustrarate.

[Neilw_05]

Here is a sample of the concept. This file is in C3D 2010. If you cannot use it I'll put together a diagram and post the graphics.

[darkman257]

I am following to a certain degree.  This might sound silly but after I traced the perimer of the two pads, one at elevation 1007 and the other at 1002, the feature line I drew went to 1004 across all points.  Is there a way that the points that I have traced along the existing feature lines snap to the same elevation?

[Neilw_05]

It doesn't make sense that the feature line did not use the elevations of the pads when you snapped to them, so I can't address that, but..

If you look closely at the sample I posted you will see that I did not "trace" the pads with a feature line. There is only one feature line around the perimter and the vertices vary according to the pad elevations. If you do trace your pads, delete the original pads afterwards or put them in a seperate site so they don't influence the perimeter feature line, as we discussed in your other post. If necessary, use elevation editor or other means to assign the pad elevations to the perimeter feature line.

[Neilw_05]

In reply to connie,

Theoretically C3D could be made to accomplish your task with gradings if it weren't for it's performance and stability problems.

Here is how it would work:

1) Create a temporary grading target surface and paste the EG surface to serve as a base.

2) Create each pad as a grading group and target the temp surface in step 1. Create a surface for each pad from the grading group. Start with any pad for the process, but for clarity we'll start with the lowest pad.

3) Paste each pad into the temp surface as you build them, starting with the lowest. As each pad is pasted, the temp surface updates to include the pad and it will be part of the target for the next pad. This way each pad will dynamicly form around the previously pasted pads. If for some reason you need to change the pasting order (i.e. Pad 1 now needs to target Pad 2), you can adjust the pasting order (in 2010 and later).

To get a finished surface, create a final surface, paste in EG and then all the pad surfaces. The finished surface will dynamicaly reflect all the gradng transitions created by the temp surface.

While this should work, you will probably experience instability problems and will have to abandon the approach.

Follow up:

After contemplating this scenario I've come to realize it can't work. The reason is that once you paste a pad to the temp surface you create a circular reference situation since the pad is influencing the very surface it targets. It is a fundamental weakness in the C3D paradigm that we can't do this. (Note, Bentley's site modeling software does provide this capability without the circular reference problems).

You may find a solution using alignments, profile and corridors to create a dynamic drape surface to use for assigning elevations to the feature lines.

[darkman257]

I think it had to do with the stacked feature lines even though each pad has its own site, individual feature line and grading group. 

So what I did then was I traced my pads, individually, using pline.  I then assigned an elevation to each of those pad's pline for my final elevation.  I then did offset, 0.1, and clicked outside of it.  I then deleted the original tracing.  I also got rid of the the feature lines and sites that i had for each pad at that final elevation to try and not confuse the poor program.  I then drew two polylines to create the "ramp" so to speak between the two pads.  I clicked on create a feature line and traced the pline manually from edge to edge.  Set it to its own site and created a grading group with targe surface to the original surveyed contours using cut/fill at 4:1.  I then created another feature line called breakline 1 to connect the open pad at the top and added it as a standard breakline to the surface created in the grading group.  I then created another feature line, breakline 2 to connect the open bad on the lower level and added it to the surface.  I then did infill on the grading for both pad areas.  I have attached a picture of what I am seeing.  I think I am getting closer but something is missing.  Thoughts?

Thanks for your patience.  Also I dont know if connie will respond.  I think I added to an existing thread from 2008 while trying to research this concept and thought process.

[Neilw_05]

Darkman,

It looks like you are close. You will need to add an infill to the open area between the pads. That will take care of the hole.

Also your TIN is not honoring the boundary created by the daylight grading at the NE corner of the pads. If you follow the steps I posted earelier you should this to work.

Create a surface from the gradings using the Create Surface toggle in the grading group properties. This will give you an automatic surface boundary at the daylight line. Then add the interior feature lines to that surface as breaklines and add the infills.

If you still can't get it, post your file and I'll see if I can make it work, then send it back so you can evaluate it. I have 2010 and 2011, but I prefer 2010. It might be best to post a stripped down DWG file with just the pad outlines as 3D polylines. I will create a dummy surface for EG so no need to send that.

[darkman257]

Sorry it has taken me this long ot get back to you.  Can you email me at caddump at gmail dot com?  I will reply to you and provide you the naked file for my lack of understanding.  I did get the infill to work on the sloped "ramp" but I could not see why my boundary was not respected.  The 3D rendering did not go too hot either.   Thanks again for the help.  I don't think this would cause an issue but the OFFSETGAPTYPE was 0 instead of 1.