Learning CAD with Alibre Atom3D

Just seen you were able to get the link posted, as you have so many undefined (constrained) items I would add constraints to the group of circles and then dimension the top right one as 0,0 from the top of the ref line.

If you can put the actual Alibre file in dropbox David or myself can show you.

Your screen shot has almost all the items in red which means they have not been constrained which is bad practice.

In video below I have first constrained the circles by giving them a Diameter and also dimensioned the distances between them. This allows me to then click on any of the circles and while holding the mouse down drag them around the screen as a group but they will not be fully defined as none are positioned to a set dimension.

I then enter two dimensions to the previously constrained guide line and the group moves there and turns black as they are now fully constrained

For a quick method - Emgee's tip (which I had forgotten all about) is probably simplest.

For ease of future editing, Jason's suggestion to fully define the positions is a good one.

My earlier comment about using 3D pattern doesn't apply to the example you have shown.

Thanks Emgee, that is just what I was looking for... I figured there had to be a way.

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Jason,

Thanks also but you are missing my point. I use constraints always (Fusion 360 pretty much dictates that you do). My issue was after having created an array of whatever and later having to move that array to a different location. Constraints in Alibre also do not seem to work with multiple selections so I cannot select the array and then apply a constraint... or can I? I realize I will need to spend more time RTFM or at least the help text but some of these things should be a bit more obvious. Again referring to Fusion 360, things are complete and located in a logical fashion.

Don't get me wrong. I enjoy Alibre Atom3d and trying to see how much I can do to squeeze everything out of the $99 (US) version. I have been working with my grandkids and trying to find an inexpensive yet complete 3D package for creating 3D printed widgets. Atom 3D is almost that perfect package (say over TinkerCad and Moment Of Inspiration) which the kids are working with now. I am trying to learn all the work-arounds to conquer what I perceive, either correctly or not, as short comings. That is why I am looking here.

Thanks again.

ADDENDUM. Jason, just saw your last post. It sounds to me like I can do what I need. As far as not having items on my sample constrained, I did not do so as I was just trying to explain the inability of moving multiple entities at a time

Edited By Robert Stout on 03/11/2019 17:31:43

Edited By Robert Stout on 03/11/2019 17:36:35

I was only going by what you linked two, that only has the 1" and 2" lines (black) constrained the rest being red have no constraints.

You would also do better sketching the array of circles separately to the ellipse and lines, that way you can just click "select all" and copy, paste, drag, etc them around as one rather than having to select each one while holding shift.

Jason, your video explains a lot. I did not seem to be able to apply a constraint to multiple entities so I will need to play with that. That is exactly what I perceived as missing. That is much better practice than moving the group as you state, but I wasn't having luck just applying a constraint to multiple selections. Back to it. Thanks again.

Jason,

Excellent, I now understand what I was doing wrong and what you meant about individual entities being under constrained. A definite misunderstanding on my part on how thoroughly parts need to be constrained.

I have just bought a 3D printer and got it running. I have downloaded several objects from the web to print. I want to modify one of the designs, is it possible to import a stl file into Alibre Atom3d? I have tried but cannot see a way of doing it. I can export parts drawn in Alibre as stl files though. Thanks for any help John

No

What Jason said.....

There are a few free editors out there such as Meshmixer that can be used to do some editing of STL files.

To edit a STL with Alibre Atom3D you will first need a program to convert the mesh to a vector file that Alibre can import.

Blender can convert a STL to a DXF.

Both Fusion 360 and freeCAD can convert STL's to STEP files.

Struggling with this myself at the moment and not found a reliable way of doing it! I've not found a simple tool that allows STL to be modified in a straightforward human way. STL is machine generated, and the editors I've seen address repair needs rather than major surgery. Hope someone knows different!

In theory (and occasionally in practice), FreeCAD is capable. Done by importing a mesh, converting to a solid, editing the solid, then exporting a new STL. In FreeCad, open the Part Workbench and create a new empty document. Then do File->Import and select the STL file. Once loaded, do Part->Create Shape From Mesh. Once that's done, other menu options switch on, notably 'Part->Convert to solid' and 'Check Geometry'.

Try 'Part->Convert to solid'. If this works it will create a 3D CAD object that can be freely edited in FreeCAD's Part and 'Part Design' Workbenches, or exported to another CAD package. Then the new solid object can be converted back to STL.

A similar workflow is possible in Fusion 360. No doubt other CAD packages can do the job too. However, F360 fails with what I'm doing in exactly the same place. It also gags on my STL files.

The problem lies in getting STL converted into a mathematically valid solid. STL describes objects as a stack of layers. These have to be stitched back together to make a CAD editable solid, that is one consisting of correctly closed faces joined together to define a closed object rather than a shell with holes in it. Converting solid to STL is much easier than reversing STL back to a solid, hence the difficulties.

If FreeCad can't 'Convert to solid' because the STL is flawed, try 'Check Geometry': this does a sanity check and automatic repairs, after which 'Convert to solid' may work. I'm not having much luck with it, maybe because I'm attempting highly complex shapes. (Glyphs converted to mesh converted to solid). Picture is of a very simple example, the letter 'W' extruded from a base, shown as opened in FreeCad's 'Mesh Builder' workbench. The mesh envelope is mostly good apart from the join between the two 'V's being broken, plus more trouble where it joins the base.

FreeCad's Mesh Builder workbench has an 'Analyze' function that evaluates and repairs broken meshes. Not had much luck with that either, mainly because I'm stumbling around in the dark. In similar vein, 'Blender' is worth a look. It too can convert STL into solids, and identify faults, and fix them. At the moment it's all too much work: I don't understand meshes, and Blender is a monster graphics package bursting with complicated features.

TinkerCad is AutoCad's tool for 3D printing design work. Has a free/student licence and seems well thought of in the 3D community. It has a cloud-based mesh repair tool that may be smarter than the alternatives. Not tried it yet.

FreeCad has a good reputation. I've successfully imported a couple of simple curved objects, edited them, and printed without any bother. So it is possible. Perhaps your STL is more friendly than mine! Worth a go.

Probably ought to open a new thread rather than pollute Alibre.

Dave

If you want, I could try running those stl files through MoI for you, to get them into something you could play with.

Martin.

One of my rare excursions into 2D cad...

I tried to put a cross-section into a drawing (generated from a 3D object) yesterday, but no matter what I tried it only created a second drawing of my object, not a section. i followed the procedure in the help section exactly

Also, it has defaulted to first angle projection, which is fine, I can't find anything that auto-generates the 'truncated cone' symbol? What's the best way of placing one? Do I have to draw it manually?

Neil

I don't have a problem with sections but not sure if Atom has the ability do do them as well. One option is to simply draw a rectangle with one side where you want the section and then cut extrude through the whole part and" save as" Add any section lines etc with note and you can hatch the cut surface too.

Will have a look for the symbol but don't use one myself.

May as well mention at this time that Mintronics have Atom and the other Alibre software at reduced prices for those that were tempted but had deep pockets.

Thanks Jason, I can view them at sketch/assembly level using 'inspect' but the process for doing it in drawings goes through all the steps but nothing happens

It's a simple part, but a section would help show which end a threaded hole goes without potential confusion about the projection.

Neil

Will hidden detail not do if you can't get section to work, does take a bit of getting used to how to select and place the section view.

Section does work the same in Atom, watch this from about the 10min mark

Edited By JasonB on 09/05/2020 18:49:38

Neil, regarding 1st or 3rd angle, click top left for file properties, select view where you can change between 1st & 3rd then tick the box to make defalt

Neil,

1st or 3rd angle is inherited from the drawing template - except for if you don't use templates, then Jason's instructions hold.

ISO world = first angle, US = 3rd angle, unfortunately in UK we use both, so no template is likely to be 100% correct. You need to modify your template to avoid having to set it each time. In Atom3D you don't have all the editing options you might like.

Projection Cone - I have a custom symbol somewhere, unfortunately Aom3D doesn't support that nice trick.

Again if you modify the template, it only has to be done once...

Save modified templates with their own unique name to avoid them being overwritten if re-installing the software.

You could just draw a simple cone and add a small scale drawing of two elevations to the title block of your main drawing if you want to show that sort of thing. Something like this

Edited By JasonB on 09/05/2020 19:56:22