topic Re: Best way of creating a 2D model from a 3D model. in AutoCAD Forum

Best way of creating a 2D model from a 3D model.

powerspinks — Wed, 19 Jan 2022 12:57:45 GMT

Hi all,

I've looked at various ways of creating a 2D model from an existing 3D model. Here is what I've found:

FLATTEN - Works but its a bit clunky. For example the model has a bunch of 2D splines drawn in 3D space. Flatten squashes them to be rather crinkly rather than smooth. See example below (Spline flattened on left and original 3D version on the right). Is there something I can do to solve this? Otherwise this method works quite well.

FLATSHOT - Seems to only flatten Solids. Am I doing it wrong? Very little of the drawing is made of solids. SOLPROF seems to be the same.

I also tried plotting to DXB then importing using DXBIN but the monochrome format is very limiting. Also I'd like to keep the drawing elements as their relevant types (splines, Plines etc...) rather than a load of Lines. Plus I had trouble exporting them at scale.

Re: Best way of creating a 2D model from a 3D model.

tramber — Wed, 19 Jan 2022 14:49:35 GMT

I got something for you :

take the objects and move them by this method.

Base point : 0,0,0

Ending point : 0,0,1e99

Press ENTER to send the command MOVE back in action.

Select P (as Previous) for the last objects being in the stratosphere (z= at least 1e99) and bring them back on earth with :

Base point : 0,0,1e99

Ending point : 0,0,0

Done it is correctly flatten. Works good on many objects and is an official method

I even put that in a button. (not LT)

^C^C(defun c:flatit()(setq sel(ssget))(command "_move" sel "" "0,0,0" "0,0,1e99" "_move" "_P" "" "0,0,0" "0,0,-1e99")(princ))(c:flatit)

once used this button, you can send the FLATIT command in a drawing...

Edit :

Look here

Re: Best way of creating a 2D model from a 3D model.

Valentin_CAD — Wed, 19 Jan 2022 16:15:51 GMT

@powerspinks ,

@powerspinks wrote:
Hi all,

I've looked at various ways of creating a 2D model from an existing 3D model. ...

Try using the VIEWBASE command - link below.

VIEWBASE (Command)

And if you want the geometry in 2D, look at what www.cadforum.cz says:

How to Explode a ViewBase generated from a 3D model?

"The standard command EXPLODE does not work on the objects of the type "Drawing View". But you can export the whole layout to a separate DWG drawing file (with the command EXPORTLAYOUT). In this file, the individual views are now just plain block references (e.g. "CustomObjectsInViewport7_0") - these blocks can be exploded to simple entities like Line, Arc, etc. and you can edit this geometry. Of course it is no more associative (unlike the Drawing view) with the original 3D model."

Re: Best way of creating a 2D model from a 3D model.

powerspinks — Wed, 19 Jan 2022 17:34:00 GMT

Thanks. VIEWBASE is incredible. Whilst it gives me good 2D projections once I finish the command all it leaves are projections of the 3D solids. Not sure why that is.

For ref we're trying to make 2D models so we don't have to send the client our 3D models (2D will be sufficient for their needs and we don't want to give out our 3D models if possible).

Re: Best way of creating a 2D model from a 3D model.

powerspinks — Wed, 19 Jan 2022 17:35:02 GMT

Thanks. Unfortunately that LISP seems to scatter all of the elements of my drawing.

Re: Best way of creating a 2D model from a 3D model.

Valentin_CAD — Wed, 19 Jan 2022 17:38:05 GMT

@powerspinks ,

For 2D, just apply the second portion of my comment - regarding EXPORTLAYOUT.

Re: Best way of creating a 2D model from a 3D model.

tramber — Thu, 20 Jan 2022 09:34:58 GMT

You showed a spline...

this is why i sent you this solution.

Re: Best way of creating a 2D model from a 3D model.

j.palmeL29YX — Thu, 20 Jan 2022 11:41:55 GMT

@powerspinks wrote:

FLATTEN - Works but its a bit clunky. ... Is there something I can do to solve this? Otherwise this method works quite well.

If you are asked "Remove hidden Lines?" (while the flatten command), choose NO. This will improve the quality (the smoothness) of the resulting Polyline drastically.

You have obviously a project which not only includes Surfaces, Solids, Meshes, 3DFaces and other geometry which define a volume or at least Faces,. Also splines (and perhaps other Wire geometry, we don't know your model) are included. Therefore the Flatten command seems for me the best choice to get the desired result.

Re: Best way of creating a 2D model from a 3D model.

powerspinks — Thu, 20 Jan 2022 13:21:32 GMT

I did. Apologies I should've explained more clearly the drawing contains a range of elements.

Re: Best way of creating a 2D model from a 3D model.

powerspinks — Thu, 20 Jan 2022 13:22:17 GMT

Thanks. I think you're right. Its not ideal but it appears to be the best under the circumstances.