Autocad after two months of use.

[Michael Simpson Virgina]

Autocad is an extreemly powerfull tool. with all that power comes a very steep learning curve that said I have made the following observations.

First let me say that I was an autocad user way back when it was Dos. It has come a long way since then. I decided to get into Autocad because I wanted to draft plans and do 3D modeling for cnc construction ilistrations.

Observations

Corel Draw is much easyer to learn and more intuitive. Its easyer to nudge and snap parts than Autocad. However I find that slowling as I am mastering Autocad I have more control over complex operations. For instance the fillet and chamfer commands have much more control and I can do things I find almost impossible in Corel.

Autocad requires more steps for many operations than Corel. Even after mastering many command I can still do the same thing much faster in Corel. This mostly because many of the operations have many options. Since Autocad is command based many of the options must be answered as you do the operation.

Autocad has a problem with creating output. It will flip the page from portrate to landscape as it sees fit. This makes it unsuitble for use with lasers. While I did Autocad to work with my laser it was not optimal. I found it much simpler to use Corel and more accurate as to placement from the edges of the laser. I pretty much abandond use of Autocad with my laser.

I found Autocad much easyer to create anotated ilistrations with dimensions than Corel.

Ok now for 3D which is the main reason I started using Autocad.

Before I start let me preface the following with the type machine I am using. My machine is water cooled and running a Quad Core (8 threads) at 4Ghz. It has 6 GB of memeory and is running two GTX295 video cards so Autocad has full graphic acceleration. The machine when under load does not get over 36 Celcius. Even Autocad working its brains out does use much over 20% of the machines CPU power. As for Autocade I am using version 2011 and Windows 7 64bit.

Autocad has a serious memory leak problem. After I started working with complex 3D models it would slowly start eating memory until Windows would start paging to the hard drive and things would pretty much come to a hault. The only way to get the memory back is to shut Autocad down and reload the drawing.

CNCBuild4 V 1 Layout1 (1).jpg

Here is a section of my latest CNC build that I created in Autocad. This is a fully modeled piece. All parts were created from scratch then assembled. This particular piece can me worked on for about an hour before I run out of memory and have reload the application.

I have checked the forums about this and it seems that this memory leak problem has been an issue since they added the Civil Eng 3D engine to Autocad. It does not look like its going to be figed any time soon in any version.

In the above drawing I need to add bolts so I did my research and spent about 3 days working on creating the follwoing parts. The threads are true 1/4" 24. This is done by sweeping a 3D helix line with a triangle and converting to a 3D solid. This solid then is used to cut a 1/4" rod, thus creating the threads.


Nuts and Bolts Layout1 (1).jpg

Ok now for the problems. Complex objects like the threaded bolt are not handled very efficiantly. The above Beam with 20 bolts will start to slow down autocad. This worries me because my design has probably 100 bolts so I dont think I can use real modled bolts as Autocad will take a week to draw them on my screen. I will probably use hex shaps for assembled assemblies.


The worst is I needed to add 20 8" threaded rods to attach the 8020 uprights to the main beam. Just one of these threads will freeze Autocad. Still dont know how I will overcome this much less modle the 56" lead screws. Im probably going to have to forget modeling srews and use non threaded nuts and bolts and threaded rod.


The following is the Stand I created for my CNC. In this design all the parts are real except the bolts. They are just the heads. This works well enough since I wont do an exploded veiw of this assembly.


CNC Build4 Stand Layout1 (5).jpg


My goal here is to create professional drawings with exploded views as well as dimensioned drawings. It can definatly do this. I have yet to even come close to tapping the power of Autocad. There may well be ways to master the performance issues the package has.

If anyone has used other modeling package to create threaded bolts with resonable performance I would be interested in your comments.

[Dan Hintz]

This is done by sweeping a 3D helix line with a triangle and converting to a 3D solid. This solid then is used to cut a 1/4" rod, thus creating the threads.

Nuts and Bolts Layout1 (1).jpg

What, no involute curves for the threads? Wuss!

ACAD, like all other Windows applications, has become a bloated beast that can barely stand up under its own weight. The memory leaks aren't the half of it. I would do a simplified bolt for the over drawing and swap in a detailed one when you need to create a detail drawing section. That much stuff slowing it down is a poor memory management issue, particularly if you have a good video system.

[Ross Moshinsky]

The thread issue is in every 3D CAD program on the planet. It's a lot of detail and it's multiplied over and over again due to them being use frequently throughout a drawing. Just use un-threaded stuff. It's VERY common. No one wants to wait an hour to render up a drawing because of nuts and bolts.

[Jay Maiers]

The worst is I needed to add 20 8" threaded rods to attach the 8020 uprights to the main beam. Just one of these threads will freeze Autocad. Still dont know how I will overcome this much less model the 56" lead screws. I’m probably going to have to forget modeling screws and use non threaded nuts and bolts and threaded rod.

That's exactly how you should handle it unless there's a really, really good reason to use fully detailed fasteners. Even then you should model the absolute minimum amount necessary to accomplish the job and not a drop more.

Also, if you need repetitive elements (like fastener combos), consider making and using blocks instead of individual solid models. It should cut your file size and speed things up a bit.

The same theory applies to the 80/20 extrusions. Wherever possible you should ditch the fully modeled extrusion in favor of something that's been simplified. At the bare minimum you should get rid of all of the tiny little rounded corners and edges and fill in the voids.

In addition to AutoCAD, I've used Inventor and SolidWorks. While they will produce an accurate fastener, they have built-tricks to avoid doing so. With Inventor, you can create a drilled and tapped hole; instead of applying true threads to the model, the program will remember that you want that hole tapped and applied a surface texture to mimic the thread pattern. When it comes time to detail the part on a print, Inventor remembers the specs for that hole and can call it out with a leader and a note. Both programs are far superior to ACAD for machine design, but they are also lacking in other areas.

Last note: I use ACAD 2011 day in, day out, all day long. I don't think I've got the same memory leak problems that you're experiencing. I have an average of 4-6 drawing files open at any one time, most of them between 2-10Mb files. I rarely have stability or performance issues that I can't solve by turning layers on and off or simplifying the models.

[Dan Hintz]

With Inventor, you can create a drilled and tapped hole; instead of applying true threads to the model, the program will remember that you want that hole tapped and applied a surface texture to mimic the thread pattern. When it comes time to detail the part on a print, Inventor remembers the specs for that hole and can call it out with a leader and a note.

Ah, that's what I was trying to remember... it applies a bitmap to a surface, like the game Doom first popularized.

[Jay Maiers]

Ah, that's what I was trying to remember... it applies a bitmap to a surface, like the game Doom first popularized.

Yup. Unfortunately it does it without the cool soundtrack.

[Gerald Wubs]

Keep in mind that many software packages have video requirements that your super duper graphics cards will not provide. I mean, that there are approved cards, and drivers that are neccessary (yes, vital, accept no substitutes, absolutely required, critcal) for STABILITY, not speed. Check out what card you will require for your 3d modelling software. Most of the time this means a Quadro, or FireGL card, and yes, they are expensive, and, yyyyyessss, your gaming card has more grunt, but it may not work well in terms of crashing, and all kinds of other fun stuff. This does not mean that for sure your card won't work, it means that if you need to use the vendors tech support, they will ask you about this, and if you do not have an approved card and driver, you are on your own.

[Gerry Grzadzinski]

As Gerald says, AutoCAD officially only supports workstation video cards, no gaming cards at all. Having said that, it can work pretty well on gaming cards, but performance can vary greatly between cards, and even different drivers.

In the first image here, all the screws have threads, including the leadscrews. It's about an 18MB model. My old PC is a 2.2Ghz Athlon X2 with a Geforce 9800GT video card. It takes about two minutes to load the drawing, but once loaded, it's not sluggish at all. I'm using 2009, btw.
When I first created this model, though, in 2007, I had a 6800GT and it became too sluggish to work with.


AC.jpg





Now, I use bolts with no threads, as shown in the second image. You can have much more complex models if you omit the threads, with no loss in performance.

AC2.jpg

If you must use bolts with threads, here's a little tip to speed up the process.
Download them from McMaster-Carr.


One more thing that I do with AutoCAD, is create g-code with a macro I wrote. Haven't tried it in 2011, but it works in 2010 with VBA support. You can download it here.
http://home.comcast.net/~cncwoodworker/AC2GC.html

[Kevin L. Waldron]

Mandolin F-5 Exploded .jpgHave you thought about Alibre?

Lot of power for assembly work and rather in-expensive compared to others ........... also Visual Mill 5 axis works inside Alibre....... if you need cam. Rhinoceros works well for parts......... there are several new third party add-ons that make assembly much easier in Rhino as well......... also many cam packages work with Rhino.

Even Turbocad will work better than Autocad for your assembly you're doing in Autocad.......

Kevin

[Gerry Grzadzinski]

Even Turbocad will work better than Autocad for your assembly you're doing in Autocad.......

Kevin, have you ever used AutoCAD to do 3D modelling? TurboCAD isn't even in the same league as AutoCAD.

[Dan Hintz]

Kevin, have you ever used AutoCAD to do 3D modelling? TurboCAD isn't even in the same league as AutoCAD.

Aaaaand hoooowwwwww.....

[Brandon MacDougall]

Also some of the 3D animation software can excel in the 3D to Cam envioments... especially when making STL's...

[Michael Simpson Virgina]

I converted my bolts to plain cylinders and that helped alot. One thing I did do for a drawing I wanted to show threads was to draw a Helix around a cylinder. The helix is a simple line but its in 3D. It did not effect the performance at all. This drawing was passed through photoshop and a few filters and the threaded rods pop.


CNCBuild4 V 3 Printer (1).jpg


For print I will use conceptual drawings output in monochrom. For PDFs and web images I will use rendered drawings.

My cards support about 98% compatible. There is a performance tuner that lets you check on the options suported by your card. If I get any heavyer into this I will probably upgrade to a workstation card since I dont play games on this system. I am also thinking of upgrading to 12GB of ram.

Its very possible the memory leak has to do with the interface with the Nvida drivers. In any case it seems to be worse if I manipulate the larger 8020 beams.

Im just getting down the 3D placement. Today things just seemed to click for me. I started using simple 3d blocks to creat points where other pieces will butt.

I love Autocads ability to create multiple layouts on the same drawing.

I did purchase a RAT 7 mouse with an adjustable DPI. This works great.

[Dan Hintz]

Michael,

Check out the Space Navigator (among others) from 3DConnexion... really inexpensive mouse for 3D work, and it even comes with an API so you can create your own interfaces.

[Kevin L. Waldron]

Gerry,

Been drawing with Autocad since 1982 and now have version 2011 along with Revit and Inventor ......... I do think I know what I'm talking about.

Kevin