topic Re: FLATTEN does not hide hidden lines. in AutoCAD Forum

FLATTEN does not hide hidden lines.

Anonymous — Tue, 03 Jul 2018 13:53:35 GMT

I am trying to create a 2D isometric model from an imported 3d step model. From the top view, I have rotated the step model so that it appears to be in an isometric orientation when viewed directly down from the top. I use the HIDE command to hide the hidden lines. The I try to use FLATTEN and FLATSHOT to created my 2D drawing of an isometric orientation of the 3D step model.

When using FLATTEN, I choose Remove Hidden Lines? with a Y. This results in the full wireframe being flattened correctly but the hidden lines are no longer hidden. Does anyone know how I can get rid of the hidden lines, without having to delete every single one each time?

When using FLATSHOT and the obscure hidden lines option ticked the image appears completely distorted with some parts resembling the original model. Without obscure hidden lines being ticked, the image is much improved but shows the hidden lines and has lots of incorrect lines all over the resulting image. Does anyone know how to correct this?

Re: FLATTEN does not hide hidden lines.

Patchy — Tue, 03 Jul 2018 14:07:24 GMT

Have you tried the command VIEWBASE ?

Re: FLATTEN does not hide hidden lines.

john.vellek — Tue, 03 Jul 2018 14:15:23 GMT

Hi @Anonymous,

Viewbase as recommended by Patchy would be my first choice but I am happy to explore this issue with you. Is it possible to attach your model to a post so i can examine the behavior?

If your data needs to be private or confidential, please email it directly to me at john.vellek@autodesk.com and please include a link to this thread in your email.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: FLATTEN does not hide hidden lines.

joetully20 — Thu, 27 Jun 2024 09:30:43 GMT

I'm late to the party, I know.

I had a similar issue with a model I created. I wanted to convert a parallel isometric view of the 3D model to 2D linework that I can then work with/edit etc.

The VIEWBASE command gave me some great visuals, but it didn't give me 2d linework to work with.
The FLATTEN command didn't hide the "hidden" linework, which meant I would have had to delete/trim all of the linework manually.
The FLATSHOT command, like you mentioned, offered me a slightly distorted flattened image.

BUT, what absolutely did work for me, was tweaking the UCS before running the FLATSHOT command.

So, below I've added a step by step of what I did.

Set the view you want. In my case, it was the SW Top view (also, I had the view set to parallel).
Change the UCS. Run the UCS command, and selected 'VIEW' to reset the UCS to the current view. Therefore, if you check the viewcube, we are now in 'Top' view.
Flatten the 3D model into a 2D block. Select your 3D model and run the FLATSHOT command. A window will appear with some options available. Select 'Insert as new block', pick the foreground line colour and linetype. Deselect 'Show' under the Obscured lines heading (this hides "hidden" linework), and click Create.
Place the new 2D block. Click somewhere on the screen to set the basepoint of your new block. Select the x and y scale factor (the default value is 1, I kept it as that as you can scale it manually later if you need to). Specify the rotation angle (again, I kept the default value of 0). Your new 2D block should now be placed.
Explode the block. This is optional, but you can now click and explode the block using the explode command. You should now have a 2D version of your 3D model with editable 2D linework.

I hope this helps you or anyone else that stumbles upon this problem.

Joe

Re: FLATTEN does not hide hidden lines.

pendean — Thu, 27 Jun 2024 13:26:03 GMT

@joetully20 wrote:
...I'm late to the party, I know. ...

You have to bring donuts then 🙂