A general question about CAD

Hi, what free CAD software are people using on here please?
I'm using FreeCAD which seems quite good, and have used it to draw a number of prints now.
But soon I'll be wanting to include gears, both plain cogs as on the extruder drive, as well as
bevel gears. The documentation on FreeCAD is mainly online, and with my connection 'being ify'
on the ship I'm having trouble accessing it.
Are many people using DesignSparks (the free RS software)? If so are you finding it any good.
Thanks in advance for your replies.
Kim..

Hi Kim,

I really like OpenSCAD. It's open source and if you have (a bit) experience in programming it's quite easy to start with.

Markus

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XBee & electronics blog: [lookmanowire.blogspot.com]

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markbee
Hi Kim,

I really like OpenSCAD. It's open source and if you have (a bit) experience in programming it's quite easy to start with.

Markus

+1 to OpenSCAD And you can embed OpenSCAD scripts in FreeCAD !

regards
Andy

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Ormerod #318
www.zoomworks.org - Free and Open Source Stuff

I'm new to this whole 3D area (CAD and printing) and I am learning DesignSpark Mechanical from RS.
It seems very intuitive and flexible, so I can remember how to do things when I come back to the software.
But I'm on the learning curve so no comment for gears etc., but as it's free, well worth giving it a try.

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Ormerod #007 (shaken but not stirred!)

I've been impressed by DesignSpark so far but have not tackled anything too sophisticated yet - simple cams and the like.

It runs reasonably well on relatively lowly hardware and, as Treth mentions above, is pretty intuitive (for my previously 2d brain).

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Mark

Ormerod #350

I have been using FreeCAD and DesignSpark Mechanical in tandem to design the same simple objects and see which feels easier.

As others have said DesignSpark is simple to use with easy icon representations and feels quite intuitive, I have managed to make design easily and in some respects using the select tool in selective mode to grab only edges etc has made the work very quick. One major gripe I have though which I think will be a deal breaker for me is that it does not save the 2D sketch after extrusion. So if you want to modify a design after you have to do it in 3D and I have been caught a few times on complicated shapes where there is no 3D way to change the length of a side I want for instance. I also struggle sometimes with the "Pull" being relative to current position and not absolute but that's just my preference.

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Q. How do I get back to my sketch?

A. DesignSpark Mechanical does not save sketches for future edit. Once you create a solid from a sketch, DesignSpark Mechanical recommends that you use the Pull and Move tools to edit the solid instead of editing the sketch.

from DesignSpark FAQ


FreeCAD does feel a little cumbersome a little like using what I imagine an early Beta of SolidWorks would have felt like. Having to constrain the freedom of your whole sketch before proceeding is tiresome and a few days away from the tool I forget which constraint button I want and if it should be lines or points you select but once you get into a grove I have not found anything I couldn't design and importantly go back to and edit.

FreeCAD has some great you tube videos when you can get internet access, give them a watch to learn some tips and tricks. DeisgnSparks own tutorial coves the basics you will need and takes a very short time to go through I would recommend giving it a trial and see if it works for you. Myself I think I will keep on with both FreeCAD for heavy lifting and DesignSpark for quick and simple jobs.

Dan.

As someone that writes a lot of code openSCAD should be for me but when it comes to mechanical I just cant "see it" until I start drawing it out.

Shame about your ps there Dan - the real strength of OpenSCAD is that everything you draw has an editable size, position and orientation, you can make a list of variables at the top and use these in the primitives for drawing, then if you need to teak somethnig, just edit the relevant number and boom. Using the openGL renderer and placing a "#" in front of the primitive you're trying to position makes makes for as quick a turnaround for me as struggling to get something in the right place and orientation using just a mouse.

One big drawback (compared to ViaCAD, the only other program I've spent much time with) is that you can't just click on an edge and get a pretty fillet (quite quick to make linear fillets, or even circular ones, but more complicated interfaces than cubes meeting cylinders seems very tricky).

I mainly use a mac, so I've only dabbled with DesignSpark, and hit the wall you point out (I also find that in ViaCAD, it takes a lot of fiddling to tweak things after the fact - it was when I moaned about this to markbee that he suggested I try OpenSCAD I think - cheers Markus ) - I'll have a go with FreeCAD, but it doesn't seem to well supported on the mac :/

Cheers

Ray

Edited 1 time(s). Last edit at 01/27/2014 07:42AM by rayhicks.

Thanks Ray

Can you elaborate on

Quote
rayhicks
Using the openGL renderer and placing a "#" in front of the primitive you're trying to position makes makes for as quick a turnaround for me as struggling to get something in the right place and orientation using just a mouse.

that sounds like a useful technique.

I hope that with some time visualising the item I want in my head and then entering that in OpenSCAD will evolve. As you say the power it has is exactly what I want. I think this lunch time may be spent going through the tutorials again.

Dan.

I really like FreeCad, but I do have a problem with it (I'm using 0.13 for windows BTW) in that if I put a square block on the screen, chamfer two of the top edges, it does it perfectly..... Then try the undo button, and the design I'm working on vanishes. Which seems to happen allot of times. But it is very easy to use otherwise.

Kim..

Edited 1 time(s). Last edit at 01/27/2014 07:56AM by KimBrown.

Kim I have just tried as you sate and it does indeed disappear!

It seems to be because the design is made hierarchically from subsequent edits to the design so when you ctrl-z you remove the last layer but the tool does not automatically set the layer before to visible. If you look in the "Label & Attributes" section of tree view the last thing you did is highlighted blue and the rest are grey. After you ctrl-z select the last item and hit Space Bar "Toggle visibility" and all should reappear.

Note as I just found out don't set more than one thing visible or selection in the 3D view goes haywire.

Dan.

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falseidle
Can you elaborate on

Quote
rayhicks
Using the openGL renderer and placing a "#" in front of the primitive you're trying to position makes makes for as quick a turnaround for me as struggling to get something in the right place and orientation using just a mouse.

a liitle vague , sorry I mean using "compile (f5)" rather than "compile and render (f6)" - the former does a quick and dirty opengl rendering using your graphics card, the latter renders using the CPU only (I think) and is needed eventually to export to STL - unless you have a complex piece, the f5 option re-rendered in real time as you rotate.
If you're using f5, then adding a # in front of a line of code will make the cylinder/whatever that is drawn in that line be visible as a ghost in pink (even if it's something you're using in "difference" as a subtraction tool.) - which is very handy if you get the coordinates wrong while subtracting one part from another. In the pictures below are two views of a section through the same object, in one I've used # in front of the cone that cuts an internal ceiling, and it appears as a transparent solid in pink:



Cheers

Ray

Thank you Ray.

That was an excellent explanation and is a very helpful technique.

I am watching you tube videos and reading tutorials now to give OpenSCAD another good go.

Thanks,
Dan.

I use the free DesignSpark at home, and a more sophisticated (and expensive) CAD system at work. It's a bit of a pain because the two are similar in many ways, but the differences catch me out quite often! Three issues with Designspark so far. The first is that it renders circular parts terribly! You end up with a very definite polygon shape instead of a circle. The second is the way that entering a distance during an extrude (pull) operation adds the figure you've entered to the distance you have started to move the mouse - the entered figure should IMO be the total of the current operation - the mouse move is just to establish the direction you want to move and/or to get a preview of what it is doing. And thirdly, a couple of designs have exported an STL that has gaps and fissures, and which Netfabb reports as having errors. Netfabb was able to repair one of the STL files, but not the other - I messed around changing the design in unimportant ways until Designspark exported a usable STL. Designspark also has several limitations which I would expect from free software, (the expensive one has easy ways to create gears, threads, splines and many other things, and can also work out stresses and loadings) but is perfectly usable for most designs.

Dave
(#106)