profiling solids in perspective view

[Anonymous]

Here is my problem...when I want to define a 3d solid (basically squash it flat into 2d line art) and I am in a perspective projection as opposed to a parallel projection, AutoCAD seems to not want to give me the correct defined 2d line art from my chosen view angle. Instead the file looks as if AutoCAD created the defined 2d view from another view angle so I have lines intersecting and things just look like crap. If I define a solid in a parallel projection everthing looks fine. Any idea as to what could be the problem? I realize when you go into 3Dorbit and get things set up in a perspective projection you can't edit, pick points, etc, but I am able to do a few things such as profile. Any help would be appreciatedand and if I'm doing something wrong let me know.

Jon

[Mr T]

I think perspective view is basically for VIEWing not editing as you have found out.

Nick

[vizwhiz]

hi There

Jon,

check out the SOLPROF and SOLVIEW commands
they work well with solids (only) set up some views

in model space i think (if i can remember This correctly)
you then have to use PS to make a viewport then select

the solid objects with the appropriate VIEW current
i just did This last week (or was it This week) extracting

4 ortho (but it works for perspectives, too) view from 1x mass model

i hope This helps

Thanks

Randy

[Jon]

My problem isn't converting solids into 2d line art...my problem is that AutCAD only seems to define the solid into 2d line art as a parallel view, and not a perspective view. When I use the solprof command in a perspective view i do not get a true representation of what I am seeing on the screen. I'ts like the computer is defining the solid based on a pure parallel southeast isometric view. So what I see is not what I get. The reason I want a defined perspective view is that larger objects such as residential structures look kind of screwy if they are not defined in perspective. I can set everything up so my solid is in perspective and even do a hide...and everything looks great, but try to do a solprof of a 3D exploded cutaway of a home when it''s in perspective and things don't quite look how I need them to. I'm running out of ideas here, along with the fact that AutoCAD gives you very limited editing tools when a solid is in perspective. Thanks for all the replies though, it's nice to bounce ideas of of others.

Jon

[robfowler]

Jon, I was interested in your post and gave it a try out for myself.

It seems that when you invoke the solprof command while in a perpective view then Acad doesn't do a 2D profile, it actually creates a 3D line drawing in isometric. This is strange!

I checked this out after doing a solprof command on a relatively simple 3D model. After swiching off the model layer and hidden solprof layer I went in to model space (using 3D orbit) and was surprised to see 3D linework for the visible layer.

Seems this is a limitation of Acad in a perspective view! Funnily enough the solprof lines look OK when viewed in isometric but get screwed up in the perspective view.

Sorry I don't have a solution for you on this one but architectural models look much better in perspective and I can empathise with your frustration here.

Rob.

[Jon]

Rob,
You hit the nail on the head...I also found out that as you pan in perspective the profile lines move too...it's like the 2d line art generated isn't all on the same plane along with not really representing what a person sees in 3D perspective.I also saw the same thing when I switched between parallel and perspective. The parallel view looked fine but lines in the perspective were off. This is truely a bummer since I do a lot of line art work. Like I said earlier, on smaller items it's not too apparent but whip up a big residential structure and it looks strange to the human eye if it's not in perspective. Maybe someone at AutoDesk will address this in time.

[robfowler]

Jon, I agree with your sentiments. I used Acad 2000 at home to test out your problem with perspective profiles. When I'm back to school next week I'll try the drawing out in 2004 to see if it's the same. Somehow suspect it probably will be

Are there any ADT users out there?

Does this perspective profiling work the same in ADT?

Perhaps Autodesk are aware of this limitation but it may be worth asking across in one of their NGs about this Jon to see what other responses are.

Rob.

[robfowler]

Jon, I agree with your sentiments. I used Acad 2000 at home to test out your problem with perspective profiles. When I'm back to school next week I'll try the drawing out in 2004 to see if it's the same. Somehow suspect it probably will be

Are there any ADT users out there?

Does this perspective profiling work the same in ADT?

Perhaps Autodesk are aware of this limitation but it may be worth asking across in one of their NGs about this Jon to see what other responses are.

Rob.

[robfowler]

Sorry about the double post - a 'Page not found error' came up when I hit the Submit button first time

Rob.

[Mr T]

Basically 3D models display ok in perspective but keep 2D work in parallel.

Nick

Inventor is better for this !!!