Using SketchUp to create files to cut with on a CNC

cnc
stl
export

#1

I am using the non pro version of Sketchup. I had hoped to use it to create files (STL format is fine) that I could take to my CadCam program to run on my small home CNC. I do have Vectric Aspire, but for some things features in Sketchup would be much more convenient. I think I see the answer to my question inferred through several other posts but want to be certain I am interpreting this correctly.

So…let’s say I made a birdhouse in Sketchup. The design is fancy and has mortis and tenons for joining the various parts and Sketchup is a whiz at doing something like that. When it is done I would like to take that design and move it to Aspire to cut the parts on my CNC. I do not see an easy way to take the elements of my 3D model of the birdhouse and explode them and orient them on the same plane in a way that would translate to the CNC? In other posts about CNC’s it appears the only way to do this would be to select one part and hide everything else then save it out as an STL file to take to the CNC. Repeat this for each part of the bird house.

With a small project like a bird house that would not be too bad. For anything with a larger number of parts it would be pretty cumbersome, to say the least.

Am I reading this right or is there a more elegant way to do this?

Thanks for your time folks,

Dave


#2

Model one logical part of the birdhouse.
Stop and make that part a Group or Component.
Then model the next logical part of the birdhouse.
Stop and make that part a Group or Component.
And so on, until the model is complete.


Creating Groups and Components


Typically one nests the parts to be cut with a CNC router within the dimensional confines of the stock.
Perhaps make a copy of the model.
Therein you can Move and Rotate the groups flat on the ground plane, arranging them as needed.
Then export your STL file.


#3

Geo,

Thank you! I am new to Sketchup and saw a bit of the power of components right away, but it hadn’t dawned on me to use the feature as you described. Cool idea.

If you don’t mind, let me paraphrase this to be sure I am following you?

Perhaps start with two layers in Sketchup. One will hold my birdhouse as assembled. Call it the assembly layer. The second will hold the individual parts laid out on one plane arranged in the dimensions of my stock material. Call it the Stock layer. When I am done I could hide the assembly layer, and save only the stock layer as an STL file to import into the CAM program.

So…create the two layers…Roughly make all the individual parts of the birdhouse on the stock layer. Make each piece a component. Copy each component to the assembly layer and assemble them into a 3D model, using the tools in Sketchup to modify each piece to fit correctly. As I modify and assemble each of those components in the assembly layer, the matching components on the stock layer are being changed to match. Once I have the 3D model the way I want it, hide that Assembly layer, make sure the camera is square to my stock layer plane, and save it as an STL file to import to my CAD program? Am I interpreting your idea correctly?

Thanks so much Geo!

Dave


#4

Not quite. Every model has “Layer0” which is the primitives layer. You cannot delete it.

Draw your primitives (edges and faces) on “Layer0” push-pulling faces up into 3D shapes.
You choose whether to cut the mortises & tenons before or after PP’ing.

Then window select the object, point within selection, and right-mouse click. Choose Make Component. If you chose to replace (likely) it should now be a component instance, and still be selected. (If not, select it.) Open the EntityInfo and change the layer to your custom “Assembly” layer.

The primitives within it will still be on “Layer0” (which is as it should be, or problems occur down the road,) … but the instance “anchor” resides on the layer you set in the EntityInfo dialog.

The instance will now be shown or hidden when the layer is shown or hidden.

You should also set up likely 3 scene pages. “Work” “Assembly” and “Print” (or “Layout” or “Stock” whatever you wish.) On each scene page, “Layer0” (and any other common layers,) as well as the scene’s namesake layer are ON (visible.) The other layers are OFF. (Update the scene after making layer visibility changes!)

If you display “Scene Tabs” you can easily switch between each scene.

When it comes time to do the stock layout, open the Components manager window, click the “In Model” button, and one by one insert new instances of all the “part” components you have made.
(This is where you realize careful naming of component definitions will help.)


#5

Thanks Dan!

I will work on this on Friday! Cross your fingers. It makes sense though.

Your and Geo’s help is very appreciated!!

Dave


#6

There’s really no need to fuss with layers.

If you build the model one piece at a time, with each piece being a Component, like @DanRathbun suggested; you can have one set of Component Instances (copies) assembled as the finished birdhouse.

Place a second set of the Components arranged on the ground plane for CNC use.

Then notice the STL Export Options dialog provides the option to ‘Export selected geometry only’.


#7

Hi Dave,

I use Sketchup in preparing my ideas, to be cut on my CNC. It is easy, accurate and often I can see how parts will interact with each other. I export as a 3D DXF file. DXF is (Drawing Interchange Format, or Drawing Exchange Format) developed by Autodesk. Most CAD programs can Import a DXF. I have Sketchup Pro for this reason. It was standard in Sketchup 2013, though omitted from Sketchup Make after this date. When I export, in Options I select Autocad 2000 and check “Edges” only. Selecting Faces can create unwanted geometry. Once you have imported the Sketchup file, it now should appear as a 3D wire frame. At this juncture, you have two choices. You convert it to a 2D wire frame, or you change the 3D wire frame into a CAD solid. You acquire the 2D by viewing the geometry sideways, and erasing all but the bottom 0 layer. This is usually sufficient for routers, Changing the complete 3D wire frame into a Solid, can be more challenging, ie. planar surfacing, ect. Depending on you CAD program, this is a simple matter. Not so, for older and cheaper programs. Your CAD/CAM should be able to generate tool paths based on your strategy options, ie. Zig Zag, Advanced Roughing, Plunge Rouging… I am not sales person for BobCad, though you can download their newest V27. It now can create solids from a wire form, much easier than V26. They run specials from time to time, and you can purchase V27 for under $600.00. There are plenty of other software programs, though you will want to investigate how well they convert a wire frame into a solid. BobCad can be ackward, as you always have to select the function you want before the geometry. This is backwards to all other graphic programs, ie. Photoshop, Illustrator & Sketchup. For a simple routing operation, you will need to lay flat all of your section, nesting them for in your CAD program, for best optimization of materials.


#8

To be clear…
Prior to SU 7.1 the free version of SketchUp featured native DWG/DXF import.
But no free version of SketchUp has featured native DWG/DXF export.


#9

Hi Geo,

I downloaded 2013 Make, and it definitely has export. Since I do have the
Pro version, I used it very rarely, though I do know it works. All work has
to remain as a 2013 file.

When I export as a STL, Nothing appears on my BobCad screen. I just figure
it’s a BobCad issue, though I have no way of knowing for sure. STL has two
formates, and one of which, you can not edit.

I had issues with exporting at one time, though it cleared up after
exporting with only Edges being selected.
It would be nice to maintain a 3D object as a solid, though I have never
been able too. So far, only wire frames are accurate, and those are in DXF
formate. I have noted, when exporting as a group, or not as a group, can
effect results.

Best Regards,

Steve Clayton

Steve Clayton, Inc.
201 Rogue River Pky.
Talent, OR. 97540
541 535-4440 Ext. 707
www.steveclayton.com


#10

Make 2013 started with a Pro Trial.
IIRC the trial period back then was eight hours of run time.


#11

Hi Geo,

I can see you are correct. My old version of 2013 is Pro. It has 7.3 hours left, and that shows you, how much I have used it.
It also may have been downloaded from a third party. I suggest not to do that, unless you like malware.


#12

For those who are interested, you can see here how simple it is to convert a wire frame into a solid. I own a Haas VM-2 Bridgeport 3X, and a Router. Most of you will be machining or routing in a 2D format. I have also listed a link for converting a 3D file into a tool path. If you are on a budget, Sketchup is effective and much cheaper than Solidworks.



#13

This is new in BobCad V27

Hope this helps…


#14

Good advice !