Make2D Intersections

Hello to everyone,
I am probably discussing an issue regarding Make2D in Rhino 6 WIP, which may be noted also somewhere else.
I have tried the Make2D on these very simple objects, where the sphere slightly intersects the two parallelepipeds. When I Make 2D, intersections don’t seem to appear in the projects lines, as shown in the attached picture.
Are you experiencing the same issue?


for this to work you may have to actually intersect them with the command intersect, or you create a boolean union that these intersections become actual geometry. at least so it is in v5 still.

Thanks RichardZ,
I am not sure if this is a feasible option, if you have to draw the elevations of any type of architectural project? It might work on industrial design projects of small scale.

this is valid for any kind of geometry regardless to which extent. if you create a housing you do not just stack a few blocks and spheres into each other but you actually create, plan the precise intersections. but then again some may not, but that is how it works in rhino. if you want intersections to be recognized as such you have to tell rhino where and in such cases where you simply stack them into each other thats a simple command.

I think that the projects I am normally involved in are a little bit too complex to have the time to intersect by hand anything visible in an elevation, piece by piece:

@luca_biselli In your example are the spheres and boxes trimmed to each other, or do they inside each other? If they are trimmed to each other than the intersections will show as the edges of the objects.

Thanks David,
Objects are not trimmed. The example is attached.

Test - 01.3dm (314.6 KB)

you can define a short cut for boolean union or an alias. you can also create a macro command, that will make both a boolean or an intersection plus make 2d with one button. if thats too much effort then consider hiring somebody who does it for you.

Just to note that TechnicalView does compute “virtual” intersections (as an option), but IIRC, this relies on some “OpenGL trickery” and thus is purely visual, the actual intersection geometry doesn’t exist.

That being said, I imagine it might be possible to include virtual intersections as an option in Make2D - by first calculating all the scene object intersections and creating virtual curve geometry, then including those in the Make2D computation - but that would probably come at the expense of good sized performance (speed) hit… Only @GregArden could tell us that…

Your workaround now would be to first run Intersect and include the results in the Make2D, but both the intersect calculation as well as the Make2D could take a long time if you have a lot of objects.


Thanks Mitch, this does make sense to me. The problem seems to be the shift of the time consumption, whether being before or after the Make2D. Time consumption is of course subjective, because while I wait for the program to do something, I can do other things, almost like when rendering, where I do expect that sometime is devoted to calculations done by CPU/GPU. Probably putting an option (which would leave the user to choose/wait or not depending on the scene/model complexity) could be useful, in my opinion. I never fully understood the reason why some operations could not have a time prediction, so that the user can choose. For example…during a highly demanding command, the user could be informed of a rough estimated time. Furthermore, just as a concept, if Make2D does a virtual calculation, could it not be possible to store a part of this calculation, so that the Make2D would be faster when projecting the virtual intersections? Finally, in the past I was thinking that programs could perform series of tasks, when not actively in use by the operator (in the night for example), having a sort of selection of computations to perform, saving time during the actual active use.