USAce777

Hi

I would like to dedicate this post to all who would like to get started or already drawing in CAD.
Any tips or tricks to improve drawing plans in CAD. Also any pictures that could help.


My tips:
* Draw one side then mirror the image for the other side.
*


Thanks

SoCal GliderGuider

Use the SNAPS Luke!

CoosBayLumber

My Feedback: (1)

Ace....

There are a considerable number of forum readers with 10, 20, 30 and more years of CAD experience and to make a wholesale statement to "Draw One Side and Then Mirror", to me seems as though you have been reading too many magazines. For I just cannot remember seeing an A/C with a canopy on the topside and well as on the bottom side. Last year at the A.M.A. convention, in front of the M.A.N. booth were a three equally experienced CAD persons, all mentioning the poor reporting and across the board errors in their new CAD editor. What you have cited was one of their matters also. About four years ago, a person from Model Aviation attempted to inform the crowd on how some new standard for plans was going to be created. There were about ten CAD software persons in the audience who immediately recognized the representative was speaking from a graphics background. We had to repeatedly let him know that CAD is just different, and older, and those that have been doing plans for decades weren't about to be revised to meet some new standards. It was the A.M.A. who was going to have to adapt to established proceedures.

Many of the readers are well into creating model parts using CNC, laser cutting, and as now I read abrasive cutting also. For creating parts via a mirroring method will disturb the line direction and order of cutting. This has been explained very well by yet another reader in the Sou. Cal. area, and perhaps you ought to review his information some time. He is quite good on this subject.

I am still pretty well new to CAD software. Only been using it since the middle 1970's, and quickly found there are Zero Tricks, it is moreover based upon calculations to which the computer quietly does, or the person punching the buttons to the keyboard does. Accuracy is based upon years of knowledge and experience. I have done model plans for five different model kit distributors, to which I remain quiet about, but read on an individual basis their reactions. Each of the owners, propriators, or superintendants does not want to hear about any tricky things going on. For Tricky things mean that in one or two years from now the basis of design, or how to reproduce a plan has been forgotten. They want no surprises. It is my suggestion that before posting here, you post the same bit of information at the Autodesk web site or at CADALOG and see if the readers concur with your findings.


Wm.

SoCal GliderGuider

William has me beat by about ten years on CAD. I started in the later 80's with Acad V2.0.

I would have to say there are two distinct sides to doing CAD model plans: The first is to make a buildable set of plans. The second is to think about kit production of those plans. The production part has to be considered while you are doing the basic plans. This is where modeling experience comes in.

As to using a graphics program to make plans; yes it can be done. BUT! Don't expect that the graphic based plans can be as readily transcribed into working parts as the dedicated CAD programs. True some of the graphics programs draw in a vector format just like CAD ; the rub comes when you need to take these splined lines from the graphics drawing into CAD. Translation to DXF or WMF or even DWG just tears the heck out of them. This requires their redraw.

I'll reinforce your use of mirroring. I've taken a few bulk heads from those graphics programs and found them to be a bit asymmetrical. Also the ends of the lines don't touch (GRIPS or SNAPS). This is critical to making those production files that William speaks of.

dr_wogz

My Feedback: (3)

I'll side with Coos. I've been cadding for a number of years, (pushing 15 yrs with CAD, Corel, Illustrator, and pen & paper)). Each (person & program) will have thier own set of tricks.

There are some powerful commands in CAD land, some that make drafting easy.

Use layers.. properly
Copy, array, stretch, offset are probably my most used commands.

Be consistent. Be absolute.

Know what the drafting standards are (I've seen a few 'engineers' who take a CAD course, and think they know how to draft) Know what your end user fabricator needs / wants / requires.

Realize you can draw just about anything, even in 3D land. But you may not reproduce it in teh real world.

Tommee

...I am only drawing airplane plans in 3d using solidworks, catia and proengineer, for me it is the only way...and ensures perfect 2d drawing...in the picture is par of my telemaster fuselage, shrinked so the quality isn't best.

mikeperik

Maybe I missed something but I think USAce777's point was that you don't need to draw both sides of the plan. For instance, draw one side of the wing and then mirror it to get the full wing. This can be applied to other areas as well, but not all. For instance, I'm trying to develop plans for a Mig-3 from some 3 view images, instead of drawing both sides of the wing I just drew one side of the wing and then mirrored it. Yes there are some details that may not be on both sides of the wing but I can get the major pieces done and add details, but the bulk of the drawing is done for me.

Mike

BMatthews

I gather that there's CAD'ing for printing and then there's CAD'ing for CNC? Apparently this makes a differnance to how the drawing is done from a couple of the above posts. This would be a find thread to show the distinctions between the two. But for many of us simply producing paper drawings would be a big step forward and some basic hints would help a lot.

Some time back I did my own set of beginner's hints for TurboCAD. They can be found in post #3 of [link=http://www.rcuniverse.com/forum/m_1941845/tm.htm]THIS FAQ THREAD[/link]

SoCal GliderGuider

Might be better to think of drawing plans and CADDing parts. You can draw plans with most any graphics program and CAD programs. Taking these plans and extracting parts for cutting via CNC is where the wheat is sperated from the chaff.

If you start with CAD and keep the CNC in mind you will eliminate 95% of the work.

allanflowers

USAce777,
I think your idea to solicite CAD tips in this thread is a GOOD one. Don't be discouraged if everyone doesn't agree. Obviously some folks are heavy into creating CNC results. Many are not. Use your CAD in your own way and please do share the work and ideas with us.
For many people who may be designing in CAD but only making a model or two for themselves, the CNC part is not a big deal. I think the 'wheat vs the chaff' thing is a bit judgemental. As for 'checking' your ideas on some Autocad users site before 'daring' to post it here, that is just silly.
Allan
http://www.checkerboardair.com

Tommee

Still, I think, the easiest way is to do a 3D model, with parts drawn in 3d individually and then assembled into a full model. Then, every part can directly be saved as dxf or dwg and cnc cut.

USAce777

Yes Allan, You got my point.
I try to draw some basic plans in TurboCAD v.9.1 with 3D, it is very hard for me as I been "playing" with the program for about a half a year now.
I would like to know how to get better at it.
I still dont understand how can you take a side fuselage drawing and make ribs for the fuselage out??? Or the wing???

Help me out please...

USAce777

Something like in this post...
[link=http://www.rcuniverse.com/forum/m_3556941/tm.htm]Go Here![/link]
He takes a wire construction plane and little by little he makes all the ribs for the fuselage...

Please Explain !!!

BMatthews

Imsi sells a $40 3D tutorial CD set. If you're happy with the basics of using the program then buying the Tutorial is probably a good investment.

SoCal GliderGuider

Fuse formers and bulkheads. Wings have ribs.

Looks like he uses restrained ellipses for the fuse sections. Check the elipse command for the CAD software you have. Acad has several ways of anchoring the ellipse when you create it.

For wing ribs you can create a tappered solid wing and section it. The surface of the section can be copied to make the rib.

SydDythers

My Feedback: (5)

Hahaha USAce777, that is the thread I started. I was excited to click on it and find a better way to do formers. I was a bit dismayed when I realized it linked to my thread!

I state in that thread that Autocad is a beast to learn and I've now concluded it will be the last time I use it. I still am not happy with the fuselage formers and bulkheads. I used the ellipse and circle commands and combined them to make the various temporary templates. Then I cut out the unecessary bits to keep things light. However, it is difficult to model going from a perfectly round cowl at the front to flat sided ellipses as the plane tapers toward the tail feathers is extremely difficult to do. It would probably be easier if I had a few cross sections available of the yak 54 but good luck finding that. If Autocad only had the ability to loft surfaces, I could fudge three or four temporarly fuse cross sections and let the software interpolate between them. Thus, I am going to try and import the model as it is into Solidworks tomorrow and try its lofting capabilities. So many people seem to have success with that program along with Catia.

So, after that long winded paragraph, I'll add two tips for Autocad:

1. In Autocad, a quick way to create stringers is to draw a 3d polyline (command is "3dpoly") and connect each part along this line. Then, draw a square in the dimensions of the stringer stick (i.e. 1/4" by 1/4"). Then type the command "Extrude" and the choose the square you drew. Hit enter then type "p" on the command line. The p tells autocad to extrude it along a path. Click on the 3d poly you drew and, voila, you have a stringer that forms around the complex structures you want it attached to.

2. Well quite simply, the best possible tip I can give for anyone wanting to use Autocad for creating 3d model airplane plans is, DON"T DO IT! Try something else.

Cheers,

John

USAce777

I got another question...
How do you move so that you could draw whole set in 3D like formers for the fuse??? What do you work around???

another one...
When you have done the outline of the fuse... how do you like cover it..like with monokote???

Thanks!!!

BMatthews

I'm not 3D competent yet but I believe there's a number of ways to do airfoils or formers. If it's just a square or ellipse where each one is just a squeeze of the previous then you can just stretch or shrink to fit some "longeron" lines that define the side and top views. To move around I think you're talking about workplanes. And finally, covering the wire frame is called rendering.

USAce777

thanks very much !!!

USAce777

hey guys,
how can you take screenshot to post it here on the web???

SoCal GliderGuider

Several ways to show your cad work. The PrintScreen button will capture the entire screen to the clip board. You then have to past it into a paint program and save it as a jpg. On Windows XP you can use the MS Paint. In MS Paint you use Edit/Paste to transfer the screen image out of the clip board then use File/SaveAs to make a JPEG file out of it. I like to use Paint Shop Pro version 7 so I can crop the image to it's essentials.

The other way is to plot it to a PDF file. Much cleaner as it is a vector representation of the drawing rather that the pixelated raster screen capture.

rainedave

My Feedback: (1)

There are indeed tricks to using any and all software. They are usually learned through experience, trial and error and doing similar tasks many times over. I made my living for five years using Photoshop everyday (I know, it's a graphics app.) and I amassed hundreds of tricks for doing various tasks. FWIW the books and workshops I attended were never as useful as what I learned by simply doing.

But, that doesn't mean people can't share what they've learned. For instance, when laying out a wing planform, I have learned that it is easier to array the ribs first. Then, add LE, TE and spars. It makes trimming lines a lot easier.

The primary hurdle in learning CAD software, or anything computer related, is coming to terms with the terminology used by the designers/programmers of the software. There is nothing intuitive about computer terminology. I remember from learning Unix/Linux that the word used for any given command has no corelation to how we describe things in the lived world. One must be able to get into the mind of an engineer or programmer if you want commands to make nominal sense. And for most of us, this is not the frame of mind that we typically live in.

Having said that, CAD software is a tool. It can be used to do more than one thing, even if that differs from its original intended use (most people have used a screwdriver to open a paint can). If what you want is a set of plans that you can scale and print for the purpose of building a model then snap to grid and mirror symmetrical parts. If you believe that your design will one day be kitted by a manufacturer, then you can focus on making drawings that conform to CNC requirements. It's all going to come down to building and flying skills anyway, no matter how perfect or flawed the drawing may be.

USAce777

I still cant get to PrintScreen as Socal Glider said...Where can I find it????? Or anything also???

SoCal GliderGuider

On a PC it's one of the three keys top right between the ten-key and the qwerty keys.

USAce777

Ok, this is what i got... not professional, but still learning...
Now how can i make a line following through the top, bottom, and the sides...like picture #2??