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*stac.at.techgrafx
Message 21 of 42 (327 Views)

Re: Import CAD

02-21-2010 07:19 AM in reply to: RBartsch
I'm not buying into your delusions. You assume that no one use the OSNAP feature in AutoCAD and
will draw lines and place objects in some willy-nilly fashion. I doubt your full understanding
of AutoCAD and it's capabilities.



STAC


wrote in message news:6341034@discussion.autodesk.com...
"incredibly inefficient"?

maybe somebody should actually try bringing
a DWG detail into revit as an image for tracing
and see how easy it is- vs. muddying-up the
project file with DWG data..

and why would revit want to use those sloppy old
hand drawn lines from AutoCAD exactly the way
they are anyway?

people are just not thinking- they never do..

see the image..
*Expert Elite*
Alfredo_Medina
Posts: 2,819
Registered: ‎06-11-2009
Message 22 of 42 (327 Views)

Re: Import CAD

02-21-2010 07:42 AM in reply to: RBartsch
Facts, not biased opinions, about the image you posted:

1. The drawing on the left is not a group of 'sloppy hand drawn lines from AutoCAD' as you said. It's not drawn by hand, and the fact that a couple of lines were not trimmed is not a deficiency of the program with which it was created.
2. The drawing on the right does not look as 'trimmed and dimensioned in a modern program'. It could have been trimmed and dimensioned on the other program used on the left, too; plus, not of them is dimensioned yet, plus both programs are being released at the same time.
3. You misplaced one of the vertical lines, the one that is on the right side of the bolt. So your traced drawing is not a reliable reproduction of the original, whatever it represents. If that happened to you with a simple straight line while tracing over a small bolt detail, imagine how many lines you will misplace trying to trace over a large site plan full of splines.

Alfredo Medina
info@planta1.com
-----------------------------------------------------------------------------------------------------------------
Planta1 Revit Online Consulting | info@planta1.com | my Twitter | The Planta1 Blog
*Matt Stachoni
Message 23 of 42 (327 Views)

Re: Import CAD

02-21-2010 08:00 AM in reply to: RBartsch
And in regards to the OP's desire to redraw a title block in Revit, you are
pretty much left with option #1 (tracing a bitmap), option #2 (tracing the CAD
linework) or a new option #3, importing and exploding the linework (easy but not
recommended as a best practice).

It's up to the user to decide which option is the sanest and most efficient.

However, if I saw one of my employees turning a perfectly decent AutoCAD drawing
of a bolt fastener into an image, importing it into Revit, and taking the time
to trace over it, that person would not have that job for very much longer.

Matt
matt@stachoni.com


On Sun, 21 Feb 2010 06:35:12 -0800, Alfredo_Medina <> wrote:

>Dear Vector2
>
>What our friend is saying about a Lisp routine that does the job of creating the topography is true. I wrote one for me, too, and I explain its use to my students in my courses. Revit provides 3 ways of making a site: 1) By manually adding points with elevations , 2) By importing a drawing, and 3) By reading a list of points.
>
>The method that you are proposing (tracing over) has to do with option # 1, but it will be extremely awkward to trace over an image of a site plan, not only painfully slow and inaccurate, but also risky and unprofessional. Have you really tried? Those plans have some difficult curves, it will be a nightmare to trace it over, don't even suggest that.
>
>Option # 2, importing a drawing; you bring a 3D wireframe of a site plan, and then tell Revit to use that import to create the topography. Once created, you may erase the imported drawing. Nothing wrong with that, if it works.
>
>The other option, # 3, is the one that works with the Lisp routine. This option has the advantage that you don't need to import any CAD drawing, which is what you and others are against to. All you need is some previous work in AutoCAD before going into Revit. In AutoCAD, you need a 3D wireframe of your site plan; have all the contours elevated as per the actual elevations. Then, in AutoCAD, you run the Lisp routine. It only takes seconds to generate a list of all the x,y,z coordinates of the first and endpoint of every line or polyline segment. The routine saves the list in a .txt file. Then close AutoCAD, go to Revit > Site view > Massing and Site tab > Toposurface > Create from import > Specify points file > select the .txt file created by the Lisp routine > and Voilá! ...your topography is created in an instant. The result is accurate, since it is created with actual coordinates. Now compare this with tracing over an image!
>
>Alfredo Medina
>Online training of
>AutoCAD & Revit Architecture
>www.planta1.com
*The Dark Princess
Message 24 of 42 (327 Views)

Re: Import CAD

02-21-2010 09:37 AM in reply to: RBartsch
the lisp in question studies the entity picked (nentsel) and grabs the
z-data accordingly.

if it is a 3dface then it extracts the list of points, eliminates duplicates
if ti is a text or mtect it converts the value to a z coordinate and
searches for other entities of similar layers/values etc
if it is an attribute it searches for similar blockas and attributes and
does the same thing

if it is a 3dpoint it simply extracts it
splines/plines with text near them for height are converted into data points
at an equal interval along the spline /plines
if the spline/plines z is constant it will search for text near the points
and if only one found attempt to extract z info - otherwise it pauses and
asks the user to enter a z or indicate which object has the appropriate z
value for that entity.

output is to a x,y,z or z,x,y file, or create 3dpoints etc

we received a 3dface representation of mount royal near mcgill uniuversity
that contain about 40,000 3dfaces. the user was able to create the .txt
x,y,z file in seconds.

--
TDP

First things first, but not necessarily in that order.

The Doctor
wrote in message news:6341099@discussion.autodesk.com...
Dear Vector2

What our friend is saying about a Lisp routine that does the job of creating
the topography is true. I wrote one for me, too, and I explain its use to my
students in my courses. Revit provides 3 ways of making a site: 1) By
manually adding points with elevations , 2) By importing a drawing, and 3)
By reading a list of points.

The method that you are proposing (tracing over) has to do with option # 1,
but it will be extremely awkward to trace over an image of a site plan, not
only painfully slow and inaccurate, but also risky and unprofessional. Have
you really tried? Those plans have some difficult curves, it will be a
nightmare to trace it over, don't even suggest that.

Option # 2, importing a drawing; you bring a 3D wireframe of a site plan,
and then tell Revit to use that import to create the topography. Once
created, you may erase the imported drawing. Nothing wrong with that, if it
works.

The other option, # 3, is the one that works with the Lisp routine. This
option has the advantage that you don't need to import any CAD drawing,
which is what you and others are against to. All you need is some previous
work in AutoCAD before going into Revit. In AutoCAD, you need a 3D wireframe
of your site plan; have all the contours elevated as per the actual
elevations. Then, in AutoCAD, you run the Lisp routine. It only takes
seconds to generate a list of all the x,y,z coordinates of the first and
endpoint of every line or polyline segment. The routine saves the list in a
.txt file. Then close AutoCAD, go to Revit > Site view > Massing and Site
tab > Toposurface > Create from import > Specify points file > select the
.txt file created by the Lisp routine > and Voilá! ...your topography is
created in an instant. The result is accurate, since it is created with
actual coordinates. Now compare this with tracing over an image!

Alfredo Medina
Online training of
AutoCAD & Revit Architecture
www.planta1.com
Valued Mentor
vector2
Posts: 2,058
Registered: ‎03-28-2009
Message 25 of 42 (327 Views)

Re: Import CAD

02-21-2010 02:26 PM in reply to: RBartsch
Alfredo-

nice to see you from time to time..

i notice you make no case for importing
DWG lines into a revit project..

the only thing i understand you to be
saying is that eventhough i made the
detail look much better- it still might
not be perfect..

but imagine what it would be like if i had
linked it in and snapped to the exact same
lines.. it would have been the exact same
sloppy AutoCAD mess PLUS my whole revit
project file would have been contaminated..

and don't kid yourself about that's not how they
draw AutoCAD lines- i pulled that out of a huge
library folder of AutoCAD details used by a 10
person arch firm for the last several years..
some of the details look okay- but many do not..

listen to logic Alfredo- ANYTHING drawn in
AutoCAD needs to be rebuilt from scratch in
revit- and the best and easiest way to do that
is to lay out all the lines over the top of an
image of those lines and then clean them up..

NOBODY has yet made a case for doing it
a better way.. because i don't think they can..
but that is what i am asking to see..
*Murph
Message 26 of 42 (327 Views)

Re: Import CAD

02-21-2010 02:41 PM in reply to: RBartsch
Well in heck do you think that images comes from to start with? Are you
going out on a site with a cutoff saw and a camera taking pictures to get an
image? Or do you think Photoshop or some other image software is going to be
any more "exact"?

--

Murph
http://map3d.wordpress.com/


"vector2" wrote in message news:6341191@discussion.autodesk.com...
Alfredo-

nice to see you from time to time..

i notice you make no case for importing
DWG lines into a revit project..

the only thing i understand you to be
saying is that eventhough i made the
detail look much better- it still might
not be perfect..

but imagine what it would be like if i had
linked it in and snapped to the exact same
lines.. it would have been the exact same
sloppy AutoCAD mess PLUS my whole revit
project file would have been contaminated..

and don't kid yourself about that's not how they
draw AutoCAD lines- i pulled that out of a huge
library folder of AutoCAD details used by a 10
person arch firm for the last several years..
some of the details look okay- but many do not..

listen to logic Alfredo- ANYTHING drawn in
AutoCAD needs to be rebuilt from scratch in
revit- and the best and easiest way to do that
is to lay out all the lines over the top of an
image of those lines and then clean them up..

NOBODY has yet made a case for doing it
a better way.. because i don't think they can..
but that is what i am asking to see..
Valued Mentor
vector2
Posts: 2,058
Registered: ‎03-28-2009
Message 27 of 42 (327 Views)

Re: Import CAD

02-21-2010 03:19 PM in reply to: RBartsch
Murph-

i'm sorry but you are making absolutely
no sense whatsoever..

the issue is about how to get already
drawn AutoCAD details into a revit file..
Active Member
mikemcculley5692
Posts: 6
Registered: ‎12-02-2009
Message 28 of 42 (327 Views)

Re: Import CAD

02-22-2010 04:42 AM in reply to: RBartsch
vector2, I could care less if you are tracing a bolt detail into revit, my concern is that you are suggesting tracing a copy of an existing surveyor's work in order to design a building or site from. And in response to your comment about how others draw lines; I think that maybe you need to not compare how the rest of us draw to some 10 year old details drafted by some rookie. I would be curious to know how long you have been in the CAD world, as everyone knows, there was a time when those sloppy lines (as you call them) were all we had to draft with, not to mention, those of us who started drafting by hand.

I do agree that there needs to be a better way to do this.

Mr. Medina, could you send me a copy of the lisp routine you spoke of?

Just a Surveyor...
*Brian Winterscheidt
Message 29 of 42 (327 Views)

Re: Import CAD

02-22-2010 06:31 AM in reply to: RBartsch
On 2/21/2010 1:08 AM, The Dark Princess wrote:
> I have a lisp that takes acad survey and creates all 3d points necessary for
> revit to create topography in seconds and far more accurately...

I have a question on these lisp-to-point methods and resulting accuracy
in Revit:

I have encountered problems on creating topo in Revit where all points
obtained from a linked .dwg file are accurate, but Revit does not
triangulate/connect these points in the same order as the original .dwg,
resulting in inaccurate topography, particularly in areas of steep grade
change (retaining walls, etc.).

Do your results from this lisp method overcome that, or have you ever
encountered this problem?

--
Brian Winterscheidt
LWPB Architecture
Oklahoma City, Oklahoma
Valued Mentor
vector2
Posts: 2,058
Registered: ‎03-28-2009
Message 30 of 42 (327 Views)

Re: Import CAD

02-22-2010 11:56 AM in reply to: RBartsch
mike-

who said anything about "surveyor's work"?
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