TOPIC: 3D CAD for the home shop - Review of Onshape

3D CAD for the home shop - Review of Onshape 2 years 5 months ago #50

  • dsnyder
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SCHSM president Michael Vulpillat made several posts about a 3D CAD ( computer aided design ) system called Onshape (www.onshape.com). Michael’s posts are about using Onshape for designing patterns for sand casting. I decided to look into it.

I became a fan of 3D modeling ever since Ed Hoffman made a presentation about Autodesk Inventor a few years ago. It takes a while to appreciate 3D modeling and it takes some dedication to learn it, but I have found it to be very useful in my pursuit of building things in my home machine shop.

So first of all thanks to Ed for getting me interested and now thanks to Michael for making me aware of a new and exciting way for hobbyists like us to use this powerful tool.

Onshape changes the way 3D modeling is done and is priced. You can read all the promo material on the web site. Of course the big thing for us is that it is free to use for hobbyists. The other big thing is that it is “cloud based”, which means that you don’t download and install a program to use it. You use it in your web browser and all your design data is stored on Onshape’s computers. (I know – “paranoia runs deep”.) Therefore, there is no program setup, which makes it very easy to get started with Onshape. You just need to create a free account. The only thing I didn’t like was that they ask for a phone number. I did receive a phone call asking if I was evaluating it for a commercial account. When I said no, he said it was fine using it as a hobbyist and that was it. Of course Onshape has to make money to stay in business, so I am OK with the call.

A little background
Onshape is a startup company only a few years old. It was started by Jon Hirschtick, the inventor of SolidWorks. He left SolidWorks and assembled a team (many also from SolidWorks) of experts to form his new company. Some people think that his business model developed after seeing the success of Google SketchUp. There is also Autodesk Fusion 360, which is pursuing a similar business model and is also free for us to use. At any rate, things are changing in the 3D CAD arena and those changes are very good for the kind of things that we do.

I have been experimenting with Onshape for about one and a half weeks. I have read the tutorials, watched the videos and done some of the exercises. The Onshape team has done an excellent job with their training materials.

I have looked at and played with some of the many “workspaces” that are “public” and thus freely available. An Onshape workspace is like a project folder that holds all the information for the project including 3D part models, 3D assemblies, 2D drawings and document files. A very interesting one is a model of Elmer’s engine #5, the geared engine with a gear within a gear to achieve straight line motion of the piston rod. An Onshape user built the 3D model from the original plans and then shared it with all Onshape users.

After a few days of practice I decided to dive in and build a complete model of a hobby engine. Since I had been working on the club project AEW wall fan, which is a Stirling engine, I decided to model a Stirling engine. The plans are at www.manfreds-hobbypage.de/ . The name of the engine is “Stirling STLK1”. To provoke your interest, following is a picture of my completed model.

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The model can be “animated” so you can see all the parts moving as though the engine were actually running.

This post is way too long so I will stop for now. If there is any interest, I can write a lot more about my experience with Onshape. There are both plusses and minuses. I saved pictures of the progress of my model and I made some videos of the engine “running”.
Dan

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3D CAD for the home shop - Review of Onshape 2 years 5 months ago #51

  • MichaelV
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Great. Of course I'm interested in knowing what your take is of the pluses and minuses.
A few great points to me are the fact that it's parametric, so if designed well one can change one parameter and everything is automatically redimensioned and so on.
As you saw it supports kinematics, and fairly easily it seems (I haven't tried it yet), which Sketchup was lacking for sure.
And that is important for designing moving system, to validate motion or to check potential interference, I've had many of these problems and I had to manually represent multiple positions to check.
It also has associated applications, which allows one to do FEA (structural analysis) and CFD (thermo/aerodynamics analysis). At the end of the day I believe that is the direction of history as we really design things for a purpose. In the past computation limitation made it that we designed mechanically and then checked whether it fit the purpose (cooling, aerodynamics, energy transformation, etc..) I believe in the near future we will be able to design from the purpose first. This is an intermediary step.
These advanced applications are sometimes with a fee, but some may be free or free to hobbyists.

As for onshape I still need some capability that they don't quite have yet (create shapes from imported data file (e.g. airfoils)) but it's getting there as you can already script your own.
In sketchup I wrote my own program to do so. There are go around, I could create the shape in sketchup, export it, import it into onshape, so it's not that critical, but I am thinking that soon I may use it more and more.
Last Edit: 2 years 5 months ago by MichaelV.
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3D CAD for the home shop - Review of Onshape 2 years 5 months ago #53

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Oh and worthy of mentioning, we can work collaboratively on a project in onshape. I don't know yet whether that is a gift or a curse, but anyway it makes it possible.
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3D CAD for the home shop - Review of Onshape 2 years 5 months ago #54

  • MichaelV
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OK so I spent the last few days using onshape, in particular because I wanted to develop a mechanism and kinematics were important.
It's a bit ackward to use I'd say. I hate the "sketch" part of it, I don't want to work in 2D anymore, by now everything should be directly created in 3D. To have to create different planes with inference that don't translate from one to the other to be able to simply make a piece of wire bend at 90deg in 2 planes is just too painful. So much so that after hours of trying I just gave up, it wasn't critical, I did it more to figure the software out.
2D is what I should be getting in the end when I want to print on paper, but designing in 2D (in other words being limited to 2 vectors) is prehistoric stuff.
I am also trying to create really simple pieces that would have taken me about 5mn on sketchup, after 1 hour I still haven't been able to figure out how to do what I want (a simple horizontal stabilizer, with a fixed part in the center upon which it's hinged). Never mind that I didn't even tried to apply an airfoil in the transverse plane of it, so a simple prism would do. Really frustrating. I'll get there eventually but it's anything but intuitive.

The assembly stuff and mating joint is really cool though.
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3D CAD for the home shop - Review of Onshape 2 years 5 months ago #58

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At least Michael responded to my post. I hope a few others will join the conversation.

I don’t know how to respond to some of Michael’s objections, especially the way things are done. Just like any software if you want to use it you will have to use it the way the developers and programmers designed it. I think Onshape follows the modeling approach that professional 3D CAD programs like SolidWorks use. The software is a work in progress and the developers accept requests for features so maybe Michael can get some of his wishes. For me at least it will be very useful in the home shop.

When you explore Onshape you will see a lot of “promo” material. A lot of this material is aimed at companies that will use it professionally. These are things like version control, which you will probably want to ignore. One you should pay attention to, however, is collaboration. You can share your model very easily with fellow HSM’s (Home Shop Machinists) allowing them to view it or even change it. You can work on a model together at the same time even if you are on opposite sides of the earth and see in real time what the other person is doing. How cool is that? Have a look at a video from Onshape demonstrating collaboration.



Be careful of Onshape videos. You can easily get overwhelmed and give up. An experienced person made the video and he flies around the user interface at breakneck speed. If you are trying to learn Onshape watch a beginning video and then practice, practice, practice until you really understand what is going on.

The following is probably already well known by anyone familiar with CAD:
The basic pieces of 3D CAD are parts, assemblies and drawings. In the Stirling engine that I modeled, I first created 3D models of the various parts such as base plate, working cylinder, piston, flywheel, etc. Next you put the parts together in an assembly. Here you can check if holes line up, if there are interferences, etc. Most importantly, you can add motion capability such as a shaft rotating in a hole in another part. Ultimately, you can make a working model as I did for the Stirling engine. Finally, you can make multiview dimensioned drawings of your parts to take to the shop so you can make them. A major feature of the program is that at any point in the project changes can be made and they will carry through the whole project. For example, change the diameter or location of a hole in a part and the change will automatically be done to the assembly and to the drawing of that part.

All interaction with Onshape is done in a web browser such as Firefox or Chrome or several others, but not Internet Explorer. I did most of my work with Firefox running on 32 bit Windows XP. This worked very well. There can be issues with your computer, however. Just like 3D video games a fairly good graphics card is required as well as a fairly powerful CPU. I found that the Chrome browser took a lot more computer resources and thus assembly rotations were slow and choppy sometimes. However, even Firefox had problems when my Stirling engine model was nearing completion. The workspace had grown to 23MB because everything you do is captured. All my mistakes that had to be corrected or done over were captured and as I was learning there were a lot of them. Several times the assembly either froze or even disappeared altogether. Fortunately this was only a problem with my computer and browser. When I closed the browser and reconnected to Onshape everything was still there. There is no “clean” function in the workspace, but you can clean out all the junk (which they call unlimited undo) by making a copy of your workspace. When I did this the size went from 23MB to 2MB and all the problems disappeared.

Onshape makes a lot of hay about “everything is done in the browser”. My experience is that there can be problems with the software due to shortcomings in your computer hardware and perhaps operating system. Things are not quite as rosy as they say.

To finish off for now, here is a video of my screen showing an animation of my model engine. It shows off an incredible feature of being able to show a cross section of your assembly with the cutting plane placed anywhere you want.



Please join the conversation.
Dan
Last Edit: 2 years 5 months ago by dsnyder.
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3D CAD for the home shop - Review of Onshape 2 years 5 months ago #59

  • MichaelV
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Love it.

Now don't take me wrong I love the software, and I know one has got to go through the particular idiosyncrasies.
That assembly and animation stuff is great though.
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