Hi. I am new here and with AutoCAD.

[CVRIV]

Hello guys. I'm new to this forum and with AC as the title of this thread already states. I was using Google's SketchUp before i started using AC. I love SU and I'm pretty good with it but I need something that was better suited for product prototyping.

 

Learning AutoCAD isnt THAT bad only because I used what I learned with SU to help me through the process. I basically spent a lot of time reading and watching tutorials online. I searched for similarities between the two programs.

 

Anyways,.... here my first problem. Converting lines to polylines. I read that I should use "pedit" to do this but I am having a problem. If I draw a simple 2D square and use pedit,... it works fine. Well, kind of. It appears the command never like,... completes. I have to hit escape when done. Is that right? Here's the command line:

 

Command: pedit

Select polyline or [Multiple]: m

Select objects: Specify opposite corner: 4 found

Select objects:

Enter an option [Close/Open/Join/Width/Fit/Spline/Decurve/Ltype gen/Undo]: j

Join Type = Both (Extend or Add)

Enter fuzz distance or [Jointype] :

3 segments added to polyline

Enter an option [Close/Open/Join/Width/Fit/Spline/Decurve/Ltype gen/Undo]:

*Cancel*

 

Now here's the real problem. Say I draw a cube or anything really and then go to use pedit. It wont work. when I execute the command and go through the options,... it deletes lines and only some of the lines are converted to polylines. It will delete like two sides and it will only convert the top and bottom squares to polylines. So what I did was I deleted the sides of the cube so I was only left with two 2D squares. I used pedit to convert both of them to PL's and at first it wasn't working. It would delete a line from each. Which line it deleted was random. But now as im playing with it,... it seemed to be converting both squares to PL's now. I tried doing a cube again and it still messes it up.

 

What im trying to get at is that once I start drawing complex shapes,... I will want to convert most of it to polylines. I dont really have any plans for anything in 2D. I plan on working mostly in 3D. I need to give my prototypes faces and stuff. SU creates faces automatically where AC doesnt. I dont mind working in a 3D wireframe trype enviroment,... but I want faces fro everything so I can see how everything looks as it comes together. Also,... is there an x-ray view in AC like SU has?

 

Thanks guys. Oh also,... how come AC doesn't ask, "Convert Lines and Arcs to polylines [Yes/No]? " everytime I use pedit?

 

Thanks guys:)

[nocturne00]

first up welcome to CADTutor.

you are drawing a cub right, is it a 3D cube? or a 2d isometric of a cube.

[CVRIV]

Sorry. It's a 3D cube. I googled pedit and It all says the same thing, joins lines, arcs etc together. I didnt find anything about there being any limitations with it, object complexity etc.

 

If you draw a fairly complex model,... say a model with many polygons, how is it usually given faces?

[nocturne00]

this would be better to explain if could get some screenshots but im not in the office now, but what i know about polylines is that they should be on the same UCS plane. so the lines that you want to convert to polyines must be coplanar with the ucs plane you are currently on (the X-Y plane of your crosshair) so the lines along the Z-axis are not coplanar with your current UCS, hence they wont be converted to polylines.

 

Its a bit harder to understand and manipulate 3D in autoCAD if you are jumping in from sketchup

[ReMark]

Welcome to CADTutor CVRIV.

 

Each side of the cube can be drawn with a polyline but your UCS has to be oriented correctly. Then you can use the 3DFace command.

[CVRIV]

That makes sence. But the question now is,... well, how are 3D models usually given faces? Some lines created usign circle, rectangle etc are automatically polylines. Extruded shapes are polylines. But there are a lot of lines that will not be polylines. Or polylines touching other polylines that arent joined. How do you give the entire model a face?

[CVRIV]

Welcome to CADTutor CVRIV.

 

Each side of the cube can be drawn with a polyline but your UCS has to be oriented correctly. Then you can use the 3DFace command.

 

I know that but what if the cube was something really complex with curves and such. How would I convert the whole thing for facing?

[ReMark]

Have you tried working with revsurf or edgesurf?

[CVRIV]

Have you tried working with revsurf or edgesurf?

 

No not yet. I will read up on those. I think I will go out and get a book on AutoCAD today.

[ReMark]

A good after-market AutoCAD book is always handy to have by your side.

 

I would suggest reading up on:

 

-3D Surfaces

-Rulesurf

-Edgesurf

-Revsurf

-Tabsurf

-3DMesh

 

I'd also suggest reading up on working with the UCS.

 

What field are you working in?

[CVRIV]

A good after-market AutoCAD book is always handy to have by your side.

 

I would suggest reading up on:

 

-3D Surfaces

-Rulesurf

-Edgesurf

-Revsurf

-Tabsurf

-3DMesh

 

I'd also suggest reading up on working with the UCS.

 

What field are you working in?

 

Thanks for the advice. I am familiar with the UCS. I'm just not understanding the steps that one needs to take to build a model in 3D using AC. I mean,... I can build a model using the drawing tools but how to give them faces if the model is full of polylines and just plain lines. A model has to be made up of polygons so that I can give the model faces. I cant do that if the model is made up of just lines.

 

God my head hurts. You know what,... I will try and recreate some a model I made in sketchup and see what happens. Just play around with it.

 

As for what I do,... I dont do anything really. Well,... I do but dont. It's a long story but in a nut shell, I design computer stuff. Modding hardware,... anything from cases, watercooling components, to grills for fans and radiators. I was doing a lot of drawing in SU because it was more acurate then drawing on paper and quicker too. But SU is designed to modeling building and cities and such. It has a hard time with very small stuff. Because of this I figured I would come to AC. Plus,... I want to design and build my on CNC router so I can start prototyping.

[ReMark]

Personally, due to the nature of my job, I do not use surfaces or meshes very much. I tend to use solids as I draw mainly tanks, structural steel components for small buildings and equipment supports.

 

I think the only time I've used 3D Surfaces is in an on-line AutoCAD course that I took. The professor had us draw a lamp, chair and a table. Whoopie! LOL

 

There are other forum members who use surfaces much more than I do and I'm sure they will have plenty of good advice to offer. So, please, stick around and keep asking questions. We're here to help.

[CVRIV]

Personally, due to the nature of my job, I do not use surfaces or meshes very much. I tend to use solids as I draw mainly tanks, structural steel components for small buildings and equipment supports.

 

I think the only time I've used 3D Surfaces is in an on-line AutoCAD course that I took. The professor had us draw a lamp, chair and a table. Whoopie! LOL

 

There are other forum members who use surfaces much more than I do and I'm sure they will have plenty of good advice to offer. So, please, stick around and keep asking questions. We're here to help.

 

 

Well,... what's the difference between solids and 3D surfaces? I read about the solid command. It said that soild is mainly used for 2D stuff. I'm pretty sure thats what it read. Also,... I dont even understand what it does. You draw a square for exmaple and choose 3 points. It will create a colored area only between the 3 points, a triangle. I dont get it.

[nocturne00]

Ok here's an image of what im talkin about.

the white lines of the cube are the only ones that can be converted to polylines coz they're coplanar with your X-Y axis (see cross hair orientation)

The red lines w/c are aligned with the Z-axis of the UCS cannot be converted to polylines coz they are not coplanar with your current UCS.

you will need to rotate your UCS to reorient the UCS so you can convert them to polylines as you can see on the second image

[nocturne00]

Well,... what's the difference between solids and 3D surfaces? I read about the solid command. It said that soild is mainly used for 2D stuff. I'm pretty sure thats what it read. Also,... I dont even understand what it does. You draw a square for exmaple and choose 3 points. It will create a colored area only between the 3 points, a triangle. I dont get it.

 

Have you gone thru the basic modelling tutorials of this website?

 

http://www.cadtutor.net/tutorials/autocad/index.php?category_id=4

 

Maybe it be better that you seek your answers there or else we'll and up with a chain of questions on your thread. we've started with just polylines and now your asking about surfaces and solids. all of those can be better explained on the link. :wink:

[CVRIV]

Have you gone thru the basic modelling tutorials of this website?

 

http://www.cadtutor.net/tutorials/autocad/index.php?category_id=4

 

Maybe it be better that you seek your answers there or else we'll and up with a chain of questions on your thread. we've started with just polylines and now your asking about surfaces and solids. all of those can be better explained on the link. :wink:

 

I have not gone through the tutorials of this site yet but I have gone through tutorials of 2 other sites. I know what you mean by rotating the UCS but I just dont understand why you have to or should have to do that.

 

I went out and bought a really thick AutoCAD 2009 book today. I'm going to start reading that after I go through the tutorials of this site. Thanks for your help. If I have any more questions I will ask:) thanks.

[ReMark]

A solid would have "thickness" while a surface model would not.

[ReMark]

What is a solid model?

 

"A CAD model that is defined by the volume of an object, not by its surfaces."

[ReMark]

What is a surface model?

 

"A CAD model of an object that is defined by its bounding surfaces."

 

"A digital representation of 3D objects which have two sides and surface area, but no thickness."

 

A surface model will also not have any mass properties.