Sketch on an iPad Pro and continue to work in Rhino for Mac

Here is a thread I would like you guys please to share how you work sketching on an iPad Pro and incorporating that pen work into your Rhino CAD designs.

I only recently started to use an iPad Pro and am quite amazed by how well the Apple Pencil works.
I started to use mainly the iOS app Concepts which allows for really fantastic and quite precise pencil work, creating free form curves and even offering to work with templates.

My issue now is that unfortunately the interface between Concepts (which offers a dxf export function) and Rhino does not work to my liking (I suppose it is a limitation of the export feature of Concepts).

Maybe you could help me to clarify?

Here is what I get with a quick doodle:

Concepts iOS app on iPad Pro:

Rhino for Mac after importing dxf:

You can see the issue of all free form curves having been broken up into straight lines (very roughly) and the elliptical curve (created with the eclipse tool template in Concepts) is a rather strange shape, not broken up into straight lines but being not without issues when trying to work with it in 3D, extruding it into a surface - very cumbersome to work with:

Here is what I do so far when trying to work with iOS Concepts + Apple Pencil and Rhino for Mac:

  • design free from sketches in iOS Concepts
  • export sketches to dxf
  • import dxf to Rhino for Mac
  • rebuild every single curve with tools in Rhino (VERY laborious)

Here is a second workflow, NOT using any iOS app to sketch:

  • use the iOS + OS X app Astropad to be able to mirror the Mac screen onto the iPad Pro
  • use the Rhino for Mac command “Sketch” to sketch free hand with the Pencil on the iPad
  • directly use those sketches within Rhino

The major issue with this second workflow is that the flow and feel of the Pencil is BY FAR not natural. There is also a MAJOR amount of correction put into the Sketch command which results in substantially altered shapes from how you actually lead the Apple Pencil on the iPad, not resulting in the actual shapes you are sketching.

A third workflow I could think of to use (also including much more labour than I would want) is:

  • sketch in ANY sketching app in iOS on the iPad (I prefer Concepts and ProCreate, both do have superior pencil feel and flow and allow for very precise sketching)
  • export the sketch as an image
  • transfer the image from the iPad to the Mac (AirDrop works reasonably well for this)
  • import the image file into Rhino for Mac and trace the image file with Rhino curve tools (the VERY laborious part I try to get rid of)

Please share your ideas and workflows or any input how to improve results.
Maybe there are some quicker tools for example to translate the rather rough dxf input within Rhino into a smooth and workable resemblance of the actual sketch?

Are there any ways of adjusting the Rhino command Sketch to inherit less alterations and follow the sketching much more accurately?

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Concept is good in my opinion for the workflow with RHINO. You must experience what are the Rhino tools to maximize the DFX file imported.
I generally use the same method by which the revenue NURBS curves from the mesh.
After importing Rhino files from the DFX Concepts, first join the lines in a polyline and then turn into a NURBS curve using the CurveThroughPolyline tool (as the case of grade 3 or 5). In other cases use the arc tool, or circle from 3 points. The ellipses have imported a large number of lines, so it is more convenient NOT join curves and simply use the ellipse command.


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Can’t you export as AI or EPS?

AI would be lots better than DWF/DXF. AI curves are smooth and would eliminate all the faceted conversion.] foolishness.
The downside is they are 2D.
Are STEP or IGES available?

Hi John
The export options in concepts are: JPG (150dpi) PNG (300dpi +) PSD (Adobe Photoshop), SVG (vector) with "option without filters compatible with IA …NOT read by Rhino…)
DFX / Autodesk AutoCad wire). Optional with separate aquisto CPT / concepts Web Link) PDF (Adobe PDF, flat), and PDF (Adobe PDF, carrier routes).


Simon, these are some awesome tips to solve the major issue with broken up dxf import segmented lines.

It is now very easy to:

  • just do a quick sketch in Concepts
  • export to dxf (using AirDrop to get the file to the Mac quickly)
  • import the dxf to Rhino
  • select all imported lines at once and drop a CurveThroughPolyline command over them and delete/hide the segments

This gets pretty close to what I want :wink:

I have to figure ways to deal with defined geometric shapes in a less laborious manner than having to rebuild them one by one in Rhino …

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But Rhino could very well handle it.

If you do not know already, consider uMAke. By signing the subscription, you can export and import of 25mb file. You can make a sketch on the iPad Pro with Apple Pencil, generate 2D and 3D curves (if you want to even surfaces) and export to IGES format STP OBJ.
To consider also Shapr3D (only works with Apple pencil) . As 3D Shapr allows export for free only obj files in medium quality, a little trick is to create the curves that are used, then extrude and export the file. This way you can pull out the mesh edge and use the usual command CurveThroughPolyline .uMake Shapr3d and Onshape, can be used in your workflow with iPad Pro and Mac Rhino. For displaying the 3dm file obtained using iRhino 3D .


Ricardo, thanks for the tip using SVG and converting to Ai for a Rhino import!

Those files work beautifully within Rhino - it would be great if Rhino could read those SVG files directly.

Any possibility this will happen?

@ Simon, I have looked into the obvious candidates for CAD on the iPad Pro. Here is the outrageous thing: every single one of them is subscription based - every single one of them.

I don’t do subscriptions :frowning:
It is a real pity for these software makers - why not offer the app with only viewer capability as a freemium app and charge for each feature to users who find the app to their liking?
Many professional apps offer this purchasing model and personally I am more than happy to pay for functionality this way after.

I hope we will Rhino someday offering a companion app for the iPad Pro that goes beyond the current viewer app.

The subscription developers need to have funds to continue development. Otherwise, they would have no interest in improving the application in the future.
As I wrote, to use Shapr3D in free version, create all the curves you need, when you’re done, all estrudile and Export. Import to Rhino and extract the edges of the mesh surfaces, use the command CurveThroughPolyline and you have NURBS curves.

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I hope so too…


it would be nice.


Assuming there is a rich enough development feature set that even basic tools could be made to work (that’s a big “if”), and most of the development would be independent of Windows and Mac Rhino (meaning we would have to add developers), what would you expect to pay for an iOS version with these limited capabilities?

I’m just asking out of personal curiosity.

As for me, I would pay for a iPad version of Rhino Pro NOT provided by subscription. The functions you think they might also be limited. The most important thing would be the ecosystem. An example … I edit a curve Rhino Mac and this is updated thanks to continuity of iPad Pro …
A kind of uMAke Rhino version (uRhino … :slight_smile:
Of course, the added value of an app like Apple’s Pencil. My 2 cents

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John, I also would be happy to pay for an app that would expand functionality of Rhino for Mac OS X.

Here is a few bullets that would be important to me with use cases:

  • no subscription but 1) a full free version with limited functionality (no export and import for example, but enough functionality for potential users to determine the use of the app and decide to buy or not to buy)
  • modular purchase per in app purchases: say one person would want certain import/ export interfaces, others never need - let the user decide which app feature they would like to buy (and constantly add new features to the app as it develops, make new features in app purchases and throw the odd new feature in for free to keep users happy :wink:
  • must have feature: same UI design (optimized for touch screen and pencil use, but visually and functionally similar to Rhino for Mac for a fluid workflow)
  • fast, wireless data connection with Rhino for Mac:
    I want to design in Rhino for Mac, a free hand curve is needed, so I open the iPad, start Rhino for iOS, draw the curve and transfer it over to Rhino for Mac with as few steps involved as possible.
    The very least it should support Apple AirDrop (which can sometimes finicky, so this is not a way of transfer to rely solely on), it should do Dropbox, Mail and ideally a direct way of interchanging data with Rhino for Mac)
  • It should support its own file space, so Rhino files can be saved on the iPad Pro for presentation purposes (and even for design purposes without having a Mac around)
  • files from within Rhino for iOS should be able to be exchanged via the standard supported Apple methods via iTunes App file exchange and via iOS file share button method (share to Dropbox, Mail, AirDrop, … )
  • all basic design tools should be there and functional
  • computing intensive and advanced design modules can be left out (like 3D chamfering, filleting, advanced surface tools, …

This would allow for these major uses, expanding Rhino for Mac in functionality and making a portable device more powerful as a tool:

  • use the extra tool of the Apple pencil on a great touch screen portable device to expand Rhino for Mac functionality (free hand drawing being the most obvious choice, but also being able to annotate, sketch, mark and modify Rhino for Mac designs, like being in a meeting, having a full 3D design on your Macbook Pro and then using the pencil to annotate, sketch and comment by hand in the same design on your iPad to communicate design changes, take meeting notes, …)

  • use the iPad Pro as a presentation device (as current Rhino for iOS does but with far more flexible features with full Apple standardized file exchange via share button and iTunes)

  • use the iPad Pro as a light “on the road” design tool (start a new design, sketching out ideas, dimensions, part features on the iPad while traveling, …)

Very often in work I take the iPad with technical drawings from the office to the workshop.
I do use the excellent app Notability with technical drawings loaded and work in the shop, doing comments, markings in those drawings as necessary, while having technical specs of a product directly at hand without schlepping A1 drawings around I rather don’t want to mark up.
I also very often use those drawings on an iPad to check in the shop certain specifications, dimensions without having to run between office and workshop back and for.

Often the technical drawings are not sufficient for resolving a dimension and I go back to the desktop CAD system to quickly take some dimensions on the 3D model or check back with the tool data.
It would be fantastic if this could be done directly on the iPad Pro with a new Rhino for iOS companion app

Important is that there are no limitations on the iOS app to display and measure full fledged Rhino 3DM files that are created on the desktop with all their details as to be able to take dimensions.

There is a very neat workflow in regards of 2D “paper” documents with the iOS app Notability.
You can work with Notability on the Mac OS X, create and prepare all necessary drawings for a project, file them in a designated project folder and even annotate them on the Mac.
These changes are all automatically synced to the iPad Notability app using Apple’s iCloud.
It would be fantastic if such a functionally could be incorporated into Rhino for iOS:

  • designate a 3DM file within Rhino for Mac to be synced (and kept in sync) to the iPad and no matter what changes are done to the file on either device is kept in sync - you could do changes in a meeting/ in the workshop/ on the road and the file on the Mac would reflect that change, saving you double work time.

I hope this helps


Simon, I am all for paid apps and always prefer an app that is sold at a fixed price + offering additional functionality via in app purchase over any kind of subscription service.

  • I have found another workaround of getting those free form curves from Concepts on the iPad into Rhino:
  • export the sketch as SVG filtered from Concepts and transmit to the Mac
  • import this SVG file into Inkscape (open source app, running on X11)
  • export the file out of Inkscape via dxf (this results in a much, much better quality dxf, closer resembling the free form curves than the Concepts app own dxf export tool)
  • continue in Rhino for Mac with the CurveThroughPolyline command to rebuild broken up polylines

It is one additional step but produces higher quality files it seems.
Inkscape is a bit antiquated (rather slow) - maybe there are ways to automate this additional step (maybe an Alfred workflow).

Another quick update as I am experimenting:

  • purchase the PDF export package in Concepts app
  • export sketch as PDF (Adobe PDF, Vector Paths)
  • Rhino can DIRECTLY import these sketches

One caveat: when sketching with tools that have line weight (any tool except the “wire” tool) the outer curves of the line will be exported as closed curves, resembling the actual weighted line as drawn.

When planning to sketch for Rhino then you should ideally just use the “wire” tool instead of more pleasing looking/ feeling tools as the pen.

It works beautifully and free hand curves are directly imported as proper curves without rebuild necessary :wink:
I just have to experiment more to find out how the regular template shapes are working this way.

If you want to save the package price for the PDF export within Concepts, you can continue to just export the SVG file (filtered), import this into an app that reads SVG files and export as a PDF from there (one more step, but saving the price of a plugin if you just want to experiment).

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Everything mentioned above would be fantastic and I think it would be a great enhancement to Rhino/iRhino - and really take the ability to DESIGN to a whole new level!!!

However… I would be extremely happy with “only” the ability to sketch with the iPad Pro + Apple Pencil - as a first step (only black lines - no color, layers or anything) and somehow easily ‘import’ the result to Rhino (Mac and Win) - Airdrop, Dropbox, whatever…! For this alone I would happily pay 50…100 € (no subscription, please). I really think it’s that important. This “sketching-only” approach would be enough for me at this stage (with, of course, the current ability to import and display/inspect models from Rhino).

Is there any chance at all that this ‘simple’ “sketching-only” could make it into iRhino? @dan @marlin @bobmcneel : Take my money, please!!! :stuck_out_tongue_closed_eyes:




I don’t know how complicated it would be to do integrate this and I’m pretty sure it won’t be in our first line of priorities, but I’ve added the wish,

  • vane

Ok, thanks :slight_smile:


You’re welcome :slight_smile:!