Press and Pull Not Selecting

[ReMark]

The teacher himself cannot figure out how to solve the problem, via the Loft command, using plain AutoCAD and you want him to switch to a "modern" program like Inventor? I hope the course runs longer than 12 weeks.

[JD Mather]

Actually the modern programs like Inventor or SolidWorks are much easier to learn/use (at least for the students in my experience, maybe not for the old dogs).

[ReMark]

OUCH! The "old dog" quip. Man, you are too cruel.

 

I'll assume that in your case the students are a tad bit smarter than the normal run-of-the-mill type I've encountered in a couple of the classes I've taken.

[JD Mather]

OUCH! The "old dog" quip. Man, you are too cruel.

 

I can get away with it now that I might be considered an "old dog" having done this stuff since back before new-fangled toys, er I mean tools, like Inventor and SolidWorks, or even AutoCAD existed. Now where did my eraser go....

 

 

I am impressed that this student is still here trying, even if the going is rough. Most would have given up when it became apparent that nobody here was going to do it for them or show them the Easy Button.

[ReMark]

FYI:

 

I took yet another look at the latest file you provided and without making any changes what-so-ever (did not even change the orientation of the UCS) I was able to get the two rectangles to loft basically duplicating what JDM demonstrates in his video. That is to say I used all four arcs as guides to obtaining the final shape. If your teacher can't do it after this then he might want to reconsider what course he teaches. I'd suggest switching to Basket Weaving 101.

[inujuju]

Now, I do appreciate all of the help you guys are providing for myself, but I do not appreciate you insulting my teacher. This is his first time using AutoCad as well sense it was just introduced to our school. The person that was to teach him how to use it has been unavaliable to do so because of personal reasons. As a result, both of us are still learning and are doing our best to figure out what is wrong. Once again, I really, really do appreciate all of the help you are giving us in solving this, but please do not insult him without understanding the situation. I feel that it is just plain rude to do so, even more so on a board dedicated to helping people solve their problems, not make them feel like idiots. I am terribly sorry for the frustation this must be causing you.

 

Now, I am unable to record what I am doing for the selection so I have taken screenshots of it. This is from the "slide attempt" file, where the basic shape has already been made.

 

1. Input of "LOFT" Command

 

2. Selecting the rectangles

 

3. Both rectangles having been selected (as you see, it does not do that preview/solid object that you guys have had, rather it just remains plain)

 

4. I choose the "GUIDES" option

 

5. Still no change in shape as I select the two bottom curves (this is the same as when I select all the curves.

 

6. I hit enter and nothing changes. The code at the bottom stating "The selected entities are not valid".

 

As you guys see, I follow exactly what you did in both the pictures, instructions, and video that you have provided me yet somewhere along the process something doesn't work. After playing with the file that you've provided with the steps and everything, I have found out that I CAN LOFT the shape you've provided. As a test I deleted your red rectangle and than re-did it on the same layer with 3D polylines. After this I found I could no longer LOFT it, meaning there should be something wrong with my picks (though I'm trying to be as accurate as I can). However, you (ReMark) stated that you used my exact file and was able to still LOFT it.

 

As you can see, this is where my teacher and I are confussed because we can't figure out where my picks have gone wrong to make it no longer work. I have also tried using layers as you have but that has not worked either.

 

Once more thanks so much for all the help and I'm sorry for all the headaches I have caused over this.

[rkent]

I am so sorry but even with the pictures and step by step instructions, neither myself nor my teacher can get it to loft. If you are still willing to help me, here is a file of the shape after I have copied the arcs and added the 3D polylines. All that's left is to loft it and my teacher cannot figure out why the command isn't working.

 

[ATTACH]30938[/ATTACH]

 

The only assumption we have is that AutoCad2010 isn't agreeing with it, but we aren't too positive. The only other assumption we can make is that the polylines are not fully connected but we cannot see where.

 

I can get it to work here also, but I am on 2012 like the others. It is a possibility that 2010 cannot do this but 2012 can. I d/l your drawing and used the loft command, guides, etc......

[JD Mather]

OK, I remember wayyy back when there was some finicky stuff with Loft in 2010.

It sounds like you could be doing everything right - but AutoCAD isn't.

 

Let me see if I can devise a work-around.

Meantime have your teacher refer to the tutorials in my signature - they should work and help him get up to speed.

 

BTW students and faculty can download AutoCAD 2012 for free from http://www.autodesk.com/edcommunity - so if you have your own computer you could try exactly the same steps in 2012 and definatively test if the problem is between 2010 - 2012 or something you are doing.

[JD Mather]

OK, this is probably going to get beyond anything a beginner can do because of limitations in 2010.

First of all,

if you read the papers I linked earlier -

 

I recommend that you set delobj=0 so that your generating geometry is not destroyed when you create the solid.

This will allow trying a bunch of iterations of different attempts with minum fuss.

 

You could also create multiple copies of your existing wireframe side-by-side so that you can do each attempt on one copy at a time.

 

In the Loft command at some point an Options for Settings will appear on the command line.

Select settings and experiment with changing them - particularly Normal To

 

Now here is the tricky part

you cannot undo to get back where you started or that undos (is that a word?) the settings you just changed.

 

Try the Loft again on next set of wireframe.

Repeat with each change in settings.

 

I think in one paper a wrote about a problem that Settings might not be where you want when entering Loft, but it doesn't give you chance to change them when you first enter the command. You don't get that option until well into the command.

 

If no effort works then Surface Modeling will be required.

I would explode the polyline rectangles and loft each of the four sides as surfaces one-by-one. (actually this would be an excellent experiment to see if 2010 is going to create your geometry)

But then another problem arises as 2010 had no easy way of stitching these surface into solids.

You then have to get into Slice with Surface techniques.

 

An easier solution might be to learn a next-generation tool like Autodesk Inventor rather than fooling with an antiquated tool like AutoCAD.

Since both you and your teacher are at the bottom of the learning curve - you don't have too much vested interest in AutoCAD, therefore you would pick up Inventor technique right from the start.

[JD Mather]

Try this real quick experiment (on a copy).

Explode the two rectangles.

Loft selecting the two bottom lines of the former rectangle as the cross-sections and then the two bottom curves as the guides.

Does it create a surface?

[ReMark]

When I read the word "teacher" I guess I assume the person knows what they are talking about and has a full understanding of the subject matter. My mistake. I apologize.

 

In your case it appears that both "teacher" and "student" are novices. Might have been nice to know this up front.

[inujuju]

Thank you for the apology ReMark and I also appologize for not making it clear that both my teacher and I are new.

 

Try this real quick experiment (on a copy).

Explode the two rectangles.

Loft selecting the two bottom lines of the former rectangle as the cross-sections and then the two bottom curves as the guides.

Does it create a surface?

 

I was able to create this surface and, after playing around a bit I was able to do this piece by piece to make the shape. It's a little time consuming but it works so I'm not complaining. I am currently trying out your other method along with gettig a copy of AutoCad 2012 to try lofting it as well.

 

Thank for all the help and, just to show off my work here's a copy of the beautiful slide (though it still has some editing to be done)

 

Thanks again for all the help and I'll post back once I've tried AutoCad 2012!

[ReMark]

You're welcome.

 

Looks like the kids will have a whale of a time on that slide.

[JD Mather]

Here is one done in Autodesk Inventor - the MCAD image and as-built.

http://www.kwikmcad.com/iPictures/2008/slides/AsyFinal_kpanik.aspx

http://www.kwikmcad.com/iPictures/2008/slides/AsyFinal_pic1kpanik.aspx

 

...can you believe you can get paid for this stuff. It's a rough life.