Steve, I would send a file containing just what needs to be cut, that way you are in control of the file and which layers are on.
In addition as you already mentioned a PDF with dimensions and explanations, number of individual parts and so on. The PDF can be opened by anyone even on a mobile device.
Yes, they should be.
The IGES standard does support dimensions, but I donât think the Rhino exporter exports them. @kelvin - maybe you could add a note to this effect in the online Help here:
Note that the Default IGES export version as well as types 143 and 144 do not have âUse simple entities when checkedâ as default. You want this checked, it should make sure your circles export as circle type objects and not as NURBS curves.
I have used the âSurfcamâ IGES flavor in the past with pretty good success, but your results may depend on the receiving program and need some fine-tuning - like a DXF export does.
Those are two different applications. Wood milling may or may not involve some 3D stuff, that is a whole different ball oâ wax. But you may run into the same problems with spline conversion for 2D routing depending on the receiving CAM software.
You are asking for hard and fast rules when there arenât any really. Itâs all about getting your exports to correspond the best with your parts as well as your suppliersâ capabilities and software. Each use case will be different. That said, in general I would use 2004 Natural as a starting point, set Polycurves to export as Splines and uncheck everything in the lower section except Explode polycurves:
That way Rhino will export pretty much everything the way is is in your file without making any geometry changes. HOWEVER, with this method, you MUST check all your entities before exporting to make sure any splines are converted to lines and arcs (if your laser cutter does not support them). Save the scheme under a new name for future use.
All the above to explain that there is no âcookbook recipeâ for this stuff.
Hi,
MartinâŚI shall speak to client and get his decision on what he intends to drill after the laser cut, I advise him to cut all holes that need to align after folding, as his folding at bench with wood etc may not match the perfection of CAD. Then supply leaving them no layer decisions.
Helvetosaur.
Thanks,
Itâs all about getting your exports to correspond the best with your parts as well as your suppliersâ capabilities and software.
So I remove splines using method and script, then export, then open back into Rhino, compare to the Rhino file. Mk1 eyeball and lots of zoom, or is there a difference command ?
Speak to those with the new equipment, hope they also are up to speed on files and their new prog.
I bet something wont be straightforward.
âŚand there was I thinking select the outlines export and be done 
armed with this I have a sound set of steps to follow.
maybe others might find these export essentials useful as well.
Note that the Default IGES export version as well as types 143 and 144 do not have âUse simple entities when checkedâ as default. You want this checked, it should make sure your circles export as circle type objects and not as NURBS curves.
is this something you need to put fwd as a suggestion to the development team ?
Helvetosaur, also I see scripts are used with new buttons we can make, what do your buttons look like, may as well follow same design.
Many Thanks
Steve
Hi Steve,
The only thing I would add is that in my opinion converting splines to arcs is still the safest method for exporting 2d geometry for two reasons below.
First, If you export a spline, you donât know if the receiving CAM system will cut it as a spline or if it will be converted it to arcs first. Most legacy CAM systems do not use splines in gcode. Even newer systems still may use only arcs.
If you export arcs, you have control over the allowable tolerance or variation from the spline.
Second, and I will have to ask someone to chime in on this next point who understands the mathematical distinction better than I âŚ
Not all splines are equal and converting among spline type or degree may change the shape somewhat. You donât have any control over whether the spline will be reinterpreted to a different type or degree.
Hi,
Having spoken to the laser cutting company and mentioning all the work involved in checking for and removing splines, asking them can they accept a file without this being done they say yes.
Tempted to just supply it as it is, saving me yet more work, if they say that.
Or is this prone to problems ? ignore what they say and spend more hours getting to grips with the methods above.
Should have sent it off already but then knowing of the extra things I need to study here on splines, other work took over I could get on with easily, though that unravelled due to modern paint specs ruining the procedure and then the weather having its say as well.
Steve
That sort of depends if you ever want to get any further work done by that companyâŚ
Hi,
jodyc111âŚThat sort of depends if you ever want to get any further work done by that companyâŚ
If they say no checking required, they have latest 1 million kit and software, are you saying that because they will refuse me, or that I will see problems and refuse them ?
This item needs to be accurate to 0.25mm no more.
cdordoniâŚIf you export arcs, you have control over the allowable tolerance or variation from the spline.
Not all splines are equal and converting among spline type or degree may change the shape somewhat. You donât have any control over whether the spline will be reinterpreted to a different type or degree.
I need to see how one redraws a spline using arcs, as clearly selarc finds arcs, splines are not selected in this command so clearly are not arcs, so redrawing something that isnt an arc and wasnt suited to being one, with an arc, this I have to see and understand !
add in what Cdordoni says about it changing shape, I dont want to change my drawing do I ?
I have some in-depth understanding and redrawing to do of what I thought was done.
If one was to say draw round a french curve then redraw it with arcs keeping the shape I would initially freak out on the idea as the french curve is for curves that dont have arcs.
I will seek out videos on how splines are turned into arcs, but to get this off as its overdue I will risk what they tell me. I asked them if other clients de spline their work and was told no.
Autocad user says rhino v6 does it very quick.
However I cant find a video on how to do it in Rhino at all. Can anyone point me to a video please ?
Steve
No video, but hereâs what you need to know:
Youâll need to convert your Degree=3 (and higher), curves in Rhino before exporting them as DXF/DWG.
Your Mill/Router/WaterJet follows G-code instructions. G-code supports three movements:
1 - Straight lines
2 - Clockwise arcs
3 - Anticlockwise arc
Itâs your job to make sure youâre only send supported curves to the machine.
Lines, arcs and circles in Rhino are good to go.
Twisty Rhino NURBS curves need to be converted to arc chains. If you donât convert them, they will be approximated by hundreds of short straight lines.
Since you need more efficient Arc objects in your DXF/DWG file, youâll need to convert your wiggly Rhino curves to arc segments before exporting.
Use the Rhino Convert command.
Use these command option settings:
Output=Arcs
SimplifyInput=No
DeleteInput=Yes
AngleTolerance=0
Tolerance=0.01mm or 0.002"
MinLength=0
MaxLength=0
OutputLayer=Current
The tolerance controls how far the arcs will pull away from your NURBS curves. Your machining process and project will determine how much is OK. The distance is in current model units.
Then when you Export to DXF, use the âCAM Imperialâ export scheme for inches and âCAM Metricâ for millimeters. Both of these export simple geometry as lines and circles.
Always check your DXF file by opening it in Rhino before you send it for cutting to make sure it looks good.
Another option is to export using the IGES file format. Nearly all CAM applications support curves through IGES. Choose an appropriate IGES export option configuration for your CAM application.
Cheers
Just follow Johnâs very explicit yet concise directions above. His comments here are gold if one needs to accomplish what you are trying to do.
Hi,
They said to send IGES so that seems easier, do I ask them for the appropriate export option config, I presume they will know what to tick etc if I tell them what the options are I am presented with ?
So to double check, does IGES avoid the splines issue and avoid the need to redraw with arcs ?
Steve
The Default IGES export scheme will probably work fine.
Send them and sample file for testing purposes and see if they have any issues with it.
Yes.
Hi,
IGES default it is then,âŚhoweverâŚ
Helvetosaur said to ensure to tick setting âexport unit normal for non planar curvesâ
(see his pic.
but I cant find it for default or 143.
(click twice to enlarge max)
so default is ok but needs this, but I cant do it .
I am V5
is it a V6 thing ?
Steve
The reality is, this is between you and your CNC guy.
Youâre going to need to do a little testing with simple but representative sample files to make sure it works well for you in your specific situation.
You have all the details to need to figure this out.
Dive in!
I didnât actually say that - true itâs checked in the image I posted, but that is by⌠Default - in V6. Looks like that setting is not there in V5, I wouldnât worry about it then, and itâs only for non-planar curves (which I think you do not have).
⌠maybe, if the CNC machine can use splines in gcode.
No.
As I posted before, G-Code only supports lines and arcs.
The idea with using IGES files is your CNC service can convert the higher degree âwigglyâ curves into G-Code arc chains quickly and accurately.
If you stay with the DXF files, YOU must do the arc conversion before sending it to them.
can % in case of multi level layer name be changed for some other symbol (when exporting to dwg)? i would personally prefer _
