[vtcnc]

Well, the tube problem seems to require specific material deformation calculations for stretch, etc. which vanilla SketchUp doesn't do. It isn't material properties oriented.

That doesn't disqualify it as a CAD. There are and have been hundreds of CADs which don't do material specific deformations -- and those that do have sometimes required expensive add-ons or versions to do it.

Even then, SketchUp is extendable and it is possible someone has written material deformation plug-ins for it. I don't know, it isn't what I use a CAD for so I'm not familiar with what is available.

I have designed and built many wooden boats, and even built an ultralight plane, wood and canvas type, and pretty familiar with traditional lofting. I don't know why your plane specifically had dimensional problems. To know that would require knowing how you arrived at each shape specifically step by step in SU. For instance what was your template and precision setting when you drew it? Within that precision did you create components in a way that produced cumulative errors, etc. Did you use any Plug-ins, like Bezier, etc.?

I'm fairly certain I could draw a fuselage in SketchUp with components accurate to a considerably higher tolerance than 1/8", but it would take an understanding of why yours didn't work. I was trying to get to that by asking you about a simple procedural exercise in my last post. That wasn't answered.

It is impossible to troubleshoot a software issue without getting down to specifics of user steps to reproduce the issue. I know. I've worked in software technical support. Generally you try to simplify the case to see what is going on. Putting up a full rendering and saying it is off by 1/8" has no specific solution or cause. Procedural errors can arise in any CAD or program.

But beyond that, I'm not trying to convince you to use SketchUp, since you already have Rhino and AutoCAD which work for your specific needs and you are happy with them. Why would you want to use SketchUp it at this point?

On the other hand, there are a huge number of people who could (and do) use free SketchUp as a CAD, and get perfectly usable tolerances for the specific need.

The Engineering template has an available precision setting of "0.000" although that must be selected by the user over the default. If a person needs higher precision, free SketchUp isn't the tool to use. Get out your wallet.

On the other hand, could be you just don't use SketchUp to its capability. If you don't set the precision to a high level and happen to be in the Architectural template with a 1/64th tolerance, then yes, cumulative procedural errors can quickly get you a fit-up of + or - 1/8th. That shouldn't be a surprise. A real life tape measure graduated in 64th used to cut multiple pieces of wood laid end to end will quickly yield errors of that magnitude.

We're running pretty far afield of the original topic, which was simply an answer to the OP whether anyone uses SketchUp as a CAD, with CNC. Or the Phlatboyz G-code generator plugin as a CAM.

My answer is, yes, I do. It works for me. Lots of other people do, and I see no reason why others might not want to try it for a majority of what people do.

Users do need to learn it, and its specific methods (like any CAD), and how to avoid procedural inaccuracies, how to set it up for maximum precision, or add plugins to extend its functions. But it's free, and....

whaddya want, egg in yer beer?

[subnoize]

Well, the tube problem seems to require specific material deformation calculations for stretch, etc. which vanilla SketchUp doesn't do. It isn't material properties oriented....

I can replicate the material flow if the program doesn't violate the basic principles of keeping the object the same size during deformation! I do this for a living, every day, for the past 27 years.

My specific problem was two fold;

1. The faces deform and are corrupt after a simple solid object subtraction
2. The objects lose size reference during deformations

Now, you said you could help. Now you are whining that Sketchy Up doesn't do something I didn't ask about. Neither does Rhino without plugins and I still use it and never make a mistake doing the exact same designs.

So, if Sketchy Up wants to play with the big boys they have a lot of features they need to add, now don't they?

OK, case closed... this conversation is dead.

[ger21]

So, if Sketchy Up wants to play with the big boys they have a lot of features they need to add, now don't they?

You've been doing this for 27 years, are experienced with AutoCAD and Rhino, and you purchased Sketchup Pro thinking it could replace them???

Sketchup is not a CAD program, and doesn't claim to be. The fact that it doesn't let you draw an arc should have tipped you off to that.

[vtcnc]

Well gerry, happy to have your input, and support.

Slight difference of definitions here, I use SkethcUp on a computer as an assistance to design. I would therefore call it Computer Assisted Design. or CAD for short. It is not as sophisticated as some current CADs but far more sophisticated than some older ones -- I can still remember some DOS CADs!

And it will draw arcs, but they are segmented. That's true of all CADs. A computer screen is composed of pixels. a printer uses dots, or if a plotter, steps, And if a CNC machine, whether servo or stepper driven, discrete intervals either on a scale or encoder, or steps to a stepper. Granted, They are generally so small that they exceed the tolerance requirements of the user, but nevertheless all digital outputs are discrete units.

The only place where true arcs or circles exist are in files or machine instructions, where they may be represented by a formulaic shorthand -- a center and radius, for instance, or internally in calculations. Even then, floating point operations still have a finite discrete digital limit of significant figures.

Anyway, Sketchup does use fairly coarse divisions, particularly in the default architectural oriented template it opens with. You can increase the number of divisions in an arc to a fine level very easily by specifying how many you want when drawing a circle.

This still may not be accurate enough for some purposes, such as tangent calculation and intersections in a very critical application. In this case there are plugins developed by "TIG" which calculate using true circle and arc formulas, and allow precise intersections, etc. :

View topic - [Plugin] TrueTangents v3.0 • SketchUcation Community Forums

I haven't found I need those (at least so far) In what I've designed and made in Sketchup.

And I certainly don't think it is a CAD of the sophistication of Rhino or AC. But it is perfectly adequate for many many purposes I see here on CNCzone. Router work, foam cutting, pattern making for castings, and quite a bit of machine building, as well. It is free and easy to learn.

So I think it deserves a place here on CNCzone and yes, in the CAD section, for discussions. Not the "my CAD is better than your lousy CAD" type, but discussions where users help other users get the best out of the program, for their purposes.

There are many people in the world who cannot afford anything more expensive, and many others who may find it a good starter program to learn 3D drawing concepts through self instruction.

Thanks for your consideration.

[BAMCNC.COM]

Green with envy huh... Doubtful...

[vtcnc]

Bam, I think you're referring to a post that was deleted.

[ger21]

And it will draw arcs, but they are segmented. That's true of all CADs.

Only in the way they are displayed on the screen, not the way they are stored internally in the software.

Save a .dxf of an arc from AutoCAD, and an arc from Sketchup, and they'll contain different entities. Convert the .dxf to g-code, and the autocad arc will give you a G2 or G3 move, while the Sketchup .dxf will give you a series of G1 moves.
For a CNC machine, the G2 or G3 are far more preferable.
Personally, if you're doing 3D work and exporting .stl files, then Sketchup is just fine, if you know it's limitations. For doing 2D work, there are much better free alternatives that will give better end results. Draftsight is one.

[BAMCNC.COM]

Bam, I think you're referring to a post that was deleted.

Lol, could be, I'm using my cell phone, sorry

[vtcnc]

Only in the way they are displayed on the screen, not the way they are stored internally in the software.

Save a .dxf of an arc from AutoCAD, and an arc from Sketchup, and they'll contain different entities. Convert the .dxf to g-code, and the autocad arc will give you a G2 or G3 move, while the Sketchup .dxf will give you a series of G1 moves.
For a CNC machine, the G2 or G3 are far more preferable.
Personally, if you're doing 3D work and exporting .stl files, then Sketchup is just fine, if you know it's limitations. For doing 2D work, there are much better free alternatives that will give better end results. Draftsight is one.

Yes that's true, as I said above, true circles exist in files and machine instructions (ie G code).

I haven't used stl files yet. I've been using .dxf, .dat (airfoil coordinate type files -- which I've used for more than just airfoils), and direct G-code generation from Sketch-Up and the PhlatBoyz plugin -- and you're right it doesn't use G2 or G3.

I haven't seen Draftsight, will check it out. I do have Q-Cad (I use Linux for an OS), and TurboCAD and DesignCAD, but I particularly like working in SketchUp. If I reach the limit of what I can do in it, I'll use one of the others.

I've also written a spreadsheet for doing 4 axis hot wire work that generate G-code, and I do some hand correction, too. Four axis wire cutting doesn't have a lot of good low cost CAM software available. Particularly in Linux.

Thanks for the clarifications and suggestion.

[subnoize]

https://productforums.google.com/d/t...oV4/discussion

So, basically SketchUp can not design for objects smaller than 1'x1' without seriously running into limitations of the system (see Gully's comment). You have to manually scale up in order to not violate the internal engine's resolution.

Since the average hobby CNC is 14" x 5 3/4" (Sieg X3 w/CNCFusion Deluxe) with a resolution of 0.001", SketchUp will not produce the desired output (without serious manual manipulation) for 3D CAM unless it is a very simple, square object.

Thank you all for the discussion. The experts have spoken, and they are not me! Let us move on...

[vtcnc]

I use free version of SketchUp all the time for CNC foam cutting for pattern making.

If it doesn't do real world tube bending and materials distortion with object subtraction of the type you need, and you paid $500 for it, I'm very sorry that happened to you. I certainly wish it was the other way around. I would be mad about it myself -- and have been when I purchased other programs that were lacking in some way.

But for other purposes like the ones I use it for, it works extremely well, and with a tolerance of .001 inch, without having to juggle into the feet template.

As I've said many times already, I use the Engineering inches template. And it allows that tolerance if you set that in preferences. I don't know why the "experts" didn't mention that template or assumed it had to be in an architectural template in feet-- maybe they are all architecture oriented and don't change SketchUp starting templates....I don't know.

Frankly most CNC routers and foam cutters don't cut near that tolerance. Should the program be abolished from consideration here on this forum, because it doesn't suit some specialized CNC requirements? Better ban routers, foam cutters, and a lot of metal milling as well. Also all other CADs that have specific problems, too.

I'm going to keep using it with my CNC machines. If you can't use it, please use what works for your needs, like AutoCAD and Rhino, which you've mentioned before (well before you deleted so many of your posts).

But I don't get why you want to prevent people from using it where it does work. It is a free, wonderful tool, in my opinion, with some specific limitations for your purposes. If those limitations are not a problem for someone else doing a different kind of work, it's a great program.

[vtcnc]

Here's a complex model designed entirely in SketchUp and all parts CNC laser cut from that. Should we tell this guy not to do things like that?

Galerie :: GeeBee R3 - Fantasy Racer :: P1020186

[BurrMan]

https://productforums.google.com/d/t...oV4/discussion

So, basically SketchUp can not design for objects smaller than 1'x1' without seriously running into limitations of the system (see Gully's comment). You have to manually scale up in order to not violate the internal engine's resolution.

Since the average hobby CNC is 14" x 5 3/4" (Sieg X3 w/CNCFusion Deluxe) with a resolution of 0.001", SketchUp will not produce the desired output (without serious manual manipulation) for 3D CAM unless it is a very simple, square object.

Thank you all for the discussion. The experts have spoken, and they are not me! Let us move on...

"Serious manipulation"? Really? Ok, seriously, the solution was to work with a scaling factor. Hardly "serious manipulation".

Since the average hobby CNC is 14" x 5 3/4" (Sieg X3 w/CNCFusion Deluxe) with a resolution of 0.001"

Well, you just threw quite a few people with those big "router tables" under the bus.

Here's a hint for the experts. If you are desiring to work at .001 and higher resolutions, dont use a "polygon modeler" to do that, you need to be working in a NURBS environment.

If it doesn't do real world tube bending and materials distortion with object subtraction

Actually, a great point! Maybe we can list ANY program that does this for under $1000.00

[subnoize]

OK, now this is getting funny! Nobody read the forum I linked to and now everyone is off topic yapping about nurb'n their mamma's boy friends with buses! Or was it some large format'n cumpooter numbering cake maker?

Anyways, I have work to do....


snz:wave:

[BurrMan]

OK, now this is getting funny! Nobody read the forum I linked to and now everyone is off topic yapping about nurb'n their mamma's boy friends with buses! Or was it some large format'n cumpooter numbering cake maker?

Anyways, I have work to do....

Gotta get back to that "Serious manipulating"......

[subnoize]

Gotta get back to that "Serious manipulating"......

With yer enlarge'n format'n Cumpoot'n controlled numberererer that's as big as a bus!