Re: 2D to 3D conversion of simple CAD drawing (DXF or PDF or JPG)

[Jim]

H-Man wrote:

> AFAIK, DWF is a result of DWG which is a 2D format, or am I wrong? That
> would mean there is no depth in the drawing information and it would
> have to be created.

I don't actually know what I'm doing, but your suggestion to use Dassault
DraftSight was right on the mark, at least for the 2D drawings.

I also have what was called 'isometric' views of what looks like angled
views of the same things in DWF format.

Is that what I need to create a 3D rotatable drawing?
What would the format be for a 3D drawing anyway?

[Anonymous]

Depending on the description of the original, if it's complicated I
would simply redraw it in 3D from scratch using wireframe line-draw
and/or solids modeling software for extrusion, rotation, or any
other user-defined operatives on whatever key elements are defined.

Converting to 3D is entirely "show me, don't tell me."

If the original is not too complicated, I would simply convert and
import it into a 2D line-draw format then into a 3D wireframe or cad
program. I would then rotate two of the three or more orthographic
elements to the appropriate x.x-degree angles and move/adjust each
node within them along the x, y and z axis until they match the
primary dimensions specified in the original drawing. Then I would
"fill in the blanks" by drawing the missing lines, arcs, and other
elements between the connecting vertices in "snap" mode, avoiding
overkill. Most projects don't need a .9999 decimal point exactitude.

Once the 3D drawing is to your satisfaction, if your 3D program
allows adding dimension layers, you could add the desired dimensions
then rotate it any way you like. But if not, you could rotate it
then export it in a 2D format and add dimensions and other notations
using a 2D program.

I haven't worked with autocad since version 13, so I'm certainly way
behind the eight ball with all the uber-advanced software out there.
I have no idea what modern freeware programs might fit the bill, any
line draw program that can import/export popular 2D/3D formats would
probably work.

--
Bub

[Jim]

Anonymous wrote:

> Once the 3D drawing is to your satisfaction, if your 3D program allows
> adding dimension layers, you could add the desired dimensions then
> rotate it any way you like.

Is Trimble SketchUp freeware the best 3D program?
http://www.sketchup.com/download/

Googling, I found others, such as Bentley Microstation PowerDraft V8i:
http://www.bentley.com/en-US/Engineering+Architecture+Construction+Software+Resources/Academic+Educators+Students/PowerDraft+Download.htm

And this site had a bunch of freeware CAD drawing programs:
http://www.freebyte.com/cad/cad.htm

Sourceforge has this 3D parametric CAD modeler:
http://sourceforge.net/projects/free-cad/

And, this site seems to list a bunch of freeware CAD editors:
http://www.techsupportalert.com/best-free-cad-program.htm

If you've used a 3D CAD editor, please let us know which is best.

[Rich Webb]

There is no single "best" without specifying evaluation criteria and
weighing factors. What works well for me will be too much for some, too
little for others, or just completely wrong in another application.

The magic bullet that you're looking for, the ability to automatically
convert a 2D drawing into a 3D object, isn't there now and probably
never will be. Consider the problem of a 2D plan view of a cylinder and
a rectangular solid. They look the same, don't they? By integrating that
plan view with other elements in the drawing (side/front elevations) or
with associated meta-information (e.g., "Figure 21. Right circular
cylinder") one can visualize and then create the required 3D shape.

Personally, I've been using Bricscad to build 3D models that are then
exported into dimensioned paper-space views for manufacturing. It's
pretty easy (and fun, actually) to start with 2D PDFs from vendors of
the enclosure, connectors, power supplies, etc. and then build a model
for evaluation ("Is this connector in the way of that switch?") and
subsequent export into individual manufacturing drawings.

In Bricscad (actually, it looks like you've already found it if that's
your forum post over there), the 3D to 2D conversion is pretty easy.
Select your solid objects and then use the Quickdraw tool (under Model |
X-Solid | Tools) to create the orthogonal and iso views.

--
Rich Webb Norfolk, VA

[Jim]

Rich Webb wrote:

> There is no single "best" without specifying evaluation criteria

I agree. But, for example, the 2D program suggested is pretty darn
good for most of us. In general, a very small set of "really good"
freeware programs exist for most things we need to do.

> The magic bullet that you're looking for, the ability to automatically
> convert a 2D drawing into a 3D object, isn't there now and probably
> never will be.

There are always two magic bullets needed:
a) Conversion of PDF to CAD (e.g., to DWF or DXF)
b) Conversion of 2D to 3D

> In Bricscad ... the 3D to 2D conversion is pretty easy.

That is the kind of information I need (as testing all the software
is beyond our capabilities - so it's always best to follow in your
footsteps since you've already tested it a bit for us).

Looks like Bricscad has a free 30-day trial period:
http://www.bricsys.com/en_INTL/bricscad/

But after that, it seems to be very expensive (compared to freeware)
at about $500 to $800 depending on the features. Certainly that's
fantastically too high a price for what I need - but the 30-day
trial 'might' be worth the learning curve (that is then thrown away)
if I can't find freeware to do what I would like it to do.

[Rich Webb]

On Fri, 21 Dec 2012 17:45:10 +0000 (UTC), Jim <j...@abcdefg.com> wrote:

>Rich Webb wrote:
>
>> There is no single "best" without specifying evaluation criteria
>
>I agree. But, for example, the 2D program suggested is pretty darn
>good for most of us. In general, a very small set of "really good"
>freeware programs exist for most things we need to do.
>
>> The magic bullet that you're looking for, the ability to automatically
>> convert a 2D drawing into a 3D object, isn't there now and probably
>> never will be.
>
>There are always two magic bullets needed:
>a) Conversion of PDF to CAD (e.g., to DWF or DXF)
>b) Conversion of 2D to 3D

When I make a 3D object based on a typical PDF datasheet, I usually just
use the reader's "snapshot" tool to put a bitmap of the more-or-less
(usually "less") dimensioned image from the datasheet into a drawing's
model space. Check a few dimensions on the bitmap and scale it as
required so the numbers come out correctly. It's rare for a datasheet
drawing to have more than a few salient dimensions. The ad hoc
dimensioned elements won't be accurate to three decimal places but are
good enough for many purposes. (Sometimes it's possible to extract a
vector image from a PDF but that often seems to take more time than just
grabbing a bitmap.)

>> In Bricscad ... the 3D to 2D conversion is pretty easy.
>
>That is the kind of information I need (as testing all the software
>is beyond our capabilities - so it's always best to follow in your
>footsteps since you've already tested it a bit for us).
>
>Looks like Bricscad has a free 30-day trial period:
> http://www.bricsys.com/en_INTL/bricscad/
>
>But after that, it seems to be very expensive (compared to freeware)
>at about $500 to $800 depending on the features. Certainly that's
>fantastically too high a price for what I need - but the 30-day
>trial 'might' be worth the learning curve (that is then thrown away)
>if I can't find freeware to do what I would like it to do.

The trial version does include the 3D tools for mesh surfaces and ACIS
solids and if it's a one-off, that may be all you need. If you're using
it professionally, though, it's worth the price. You're also buying the
time of a first-rate development and support staff.

That said, I generally recommend to, e.g, people in the office that just
need to look at and maybe "fill in the blanks" on a DWG file, that they
take a look at 3DS DraftSight, already mentioned up-thread.