Drawing isometric in 2D

I'm currently taking an CAD program and as a beginning student I'm having trouble drawing a few objects in isometric perspective and would like some help. These objects must unfortunately be drawn in 2D. I've drawn the orthographic perspectives for each object based on the dimensioning given however I'm unsure how to proceed on certain portions of the drawing. This is all homework and I doubt using any customization is allowed.

The first image is a top view of a fixture. I'm having trouble with the central portion which I draw by first constructing the vertical arm then using the array command.

Is there some way to create an array of this object that respects the isoplane that I drew my isocircles in?

If not, I'm able to look at the original using the VPOINT from the 1,-1,1 point and get the perspective that I want. Is there a way to use the UCS and trace over the orthographic perspective then take that traced image back to the world X-Y plane? I've tried this before but once I get it back it simply looks like the orthographic perspective.

The following drawing I'm simply having trouble drawing one particular curve which the green arrow points to. The drawing is of two perpendicular intersecting cylinders one having a slightly smaller radius then the other and the curve in question represents the edge formed by the intersection. The research I've done indicates that it's an ellipse however I'm unsure how to draw it correctly and the one I put in is simply an estimate. How can I construct the correct curve? Even if I could change viewpoints I'm not sure I could find a way to trace this one.

Thanks in advance for any help. I'm also looking for good, free, online tutorials on how to draw 2D isometric images from orthographic projections in AutoCAD as it seems many of the sites I find are either trivial or focus on drawing by hand.

If not, I'm able to look at the original using the VPOINT from the 1,-1,1 point and get the perspective that I want. Is there a way to use the UCS and trace over the orthographic perspective then take that traced image back to the world X-Y plane? I've tried this before but once I get it back it simply looks like the orthographic perspective.

This link (http://www.cadtutor.net/forum/showthread.php?t=15032) describes a method for employing the vpoint 1,-1, 1 to automatically generate Iso projections.

The following drawing I'm simply having trouble drawing one particular curve which the green arrow points to. The drawing is of two perpendicular intersecting cylinders one having a slightly smaller radius then the other and the curve in question represents the edge formed by the intersection. The research I've done indicates that it's an ellipse however. . . .

I think that intersection will actually be a compound curve - an ellipse with a bend along the major axis. An approximation may be the best one could get with standard Iso drawing techniques. With regard to those techniques, post #10 in this link (http://forums.augi.com/showthread.php?t=67632) has an attachment that demos a method for creating Iso’s from orthographics.

Thanks for the second link seems very useful. I assume for my first drawing which is the top view that the point of rotation would be the point that I find from the extension of the bottom line to intersect with the vertical line tangent to the east quadrant of the circle which defines the corner of my drawing. I spent a lot of time last night trying to get the isocircle to break at a point so I could use the divide command to put points in the appropriate places along the curve with mixed results, so this is definitely an improvement.

As I've begun working on the isometric using the circle method I've noticed that it has some shortcomings that I'm unable to resolve. Firstly, I need to dimension the isometric so it cannot be scaled down which is a result of this method. Secondly, the isocircle option for ellipses does not produce accurate results, it seems that it's more of an estimation technique.

I've now been able to use the method you described to plot a DXB file with the correct image. However the new objects are not scaled properly and I'm not sure how to get it to plot to the size specified. I can see where the problem is arising, when I am in paper space and I trace over a line that is 0.5 units long it comes out to be another number. I've tried using zoom -> scale -> 1XP but it's still off I presume because of the modified viewpoint. I've also tried scaling the objects after they're imported into the new file by brute force but I'm not able to get sufficient precision.

I appreciate this is 2D work but it may be worth converting to 3D, drawing the circles as extrudes then intersecting them and it will have all the lines correct in a SE ISO view for example.

I teach on 'drawing boards' using isometric construction on an elevation projecting to the end elevation and then transferring those lengths cross to the isometric to create the line of intersection.

Isometric and perspective are different drawings - Isometric is projected at 30degs each side from horizontal and are parallel whereas Perspective is NOT parallel and lines goto 1,2 or more VPs (vanishing points). If you draw in 3D then you can display in Orthographic, Perspective or Isometric, alll with a few clicks, hence the move to 3D being what you really need.

HTH

Nick

As mentioned by Mr T, the final result you seek is more easily achieved via full 3D geometry.

As a 2D isometric assignment you are forced to contend with several annoying issues. The dimension issue can be resolved by scaling either the viewport's scale factor prior to DXB printing or the resulting geometry by 1.224745( Sq. Root of 3/2 to be more precise). This compensates for the geometric distortion from the offplane viewpoint.

I faced difficult problem of converting orthographic views into isometric views, Dear friend i need your urgent assistance since I have given the questions as home take exam. if you give me your email I may attach the problems and looking forward to your better help.

sincerely Yours

Zekeria Yusuf

Email: zakoyusuf@yahoo.com

Zako: You somehow managed to pull up a thread that dates back three years. If you need help with drawing a 2D isometric then post your questions and if possible an image of the object you are drawing. And it is never a good idea to post one's email address in a public forum.

As i have earnestly requested you. I don't have any experience in converting orthographic views into isometric or oblique drawings. I appreciate your cooperation in doing this assignment. Would you please convert them and send back to me.

Kind Regards,

Zekeria Y. Habib

Zako:

You should have started a new thread rather than continuing to post to an old one.

You might benefit from taking a look at a book about technical drafting. Developing views whether on a drafting board or on a computer using a CAD program will require pretty much the same approach.

Nice image but without any readable dimensions anything one of us could create would end up only being an approximation.

Have you ever drawn an isometric view of an object by hand? Do you know how to set up your drawing environment (in CAD) for creating an isometric drawing? I'm assuming you want to do this all in 2D right?

Dear friends

I presume that you might have better experience than me. This is why i am looking for your help. Would you please insert into soft ware and work it even its approximate drawing so that i may relieve. In the future we will be friends and so much to share.

cordially

Zako:

 

You should have started a new thread rather than continuing to post to an old one.

 

You might benefit from taking a look at a book about technical drafting. Developing views whether on a drafting board or on a computer using a CAD program will require pretty much the same approach.

 

Nice image but without any readable dimensions anything one of us could create would end up only being an approximation.

 

Have you ever drawn an isometric view of an object by hand? Do you know how to set up your drawing environment (in CAD) for creating an isometric drawing? I'm assuming you want to do this all in 2D right?

You presume a lot.

We'll see what we can do. In the mean time, I would respectfully ask that you respond to the questions I put to you.

How's this?

I would model as 3D and then explain to the teacher that the assignment is a holdover from well into the last century where we didn't have 3D CAD software or did everything on a drafting board. A couple of years before that we did everything with charcoal on a cave wall.

If your teacher expects you to use these ancient methods - did the teacher show you how to

set isometric grid

use F5 for toggling isoplanes

show you how to create ellipse isocircles

If I converted them for you and sent them back to you - how will that help you learn to do the ancient ways?

Zako: Is this assignment for school?

Yeah, not too bad for having no dimensions to work off of.

The image isn't going to do him much good as he doesn't have a DWG file to go with it.

Yeah, not too bad for having no dimensions to work off of.

Looks like the typical school problem where it is actually on a grid (hard to see in low res image) and the instructor

assigns a magnitude to the grid spacing.

In any case, the instructor should provide instruction on how to do similar problems before giving out an assignment.

I appreciate your cooperation in doing this assignment.

If only the internet had existed back when I was in school.

How much are you willing to pay for me to cooperate in doing this assignment for you?

Anybody else want to take a crack at one?

Just post image files no DWG files. Don't want to make it too easy.

If there was a grid in there I sure as heck couldn't see it. Of course I'm blind in one eye so I'd only see half the grid anyway! LOL

Zako,

If you really want to learn how to do this (rather than pay someone to do it for you), pick one of those parts - just one for now - and attach a better image of just that one part and indicate grid spacing.

Someone here will walk you through the process line-by-line.

Along the way you will be asked to attach dwg file of what you have completed at each step to make sure you are following the instructions correctly.

So simple!

So easy!

So logical!

Corrected image. Thank you JDM for pointing out the flaw.

Another example to muse on.

.

It is not correct - where is the large cylindrical feature?