Running 8.20.25133.14002 on Mac. Not sure when it started, but if I ask for intersection of two spheres, I’m only getting a tiny fragment of the full circle it should be; occasionally multiple fragments. See highlighted curve in this example.
Definitely used to give me the full circle. I feel like I’m being dumb and doing something wrong, but can’t figure it out. Any clues?
What are your file tolerances relative to the size of the spheres? Are they very far from the origin? Maybe post an example file.
Example file attached. Two 100mm diameter spheres on or around the origin, spaced 40mm apart. Intersection layer shows the two tiny partial curves I get if I ask Rhino to Intersect them. My tolerance is 0.001 units.
intersecting-spheres.3dm (3.4 MB)
I downloaded your file and saw the intersection fragments. I deleted those. But I get a full circle when I run the _Intersect command. (I’m on windows, if it matters). My rhino version is: 8.20.25133.14001
When two spheres intersect along the direction of two poles, a standard circle is created, similar to run the ExtractIsoCurve to extract the iso curve along the torodial direction. The same result can be obetained using the Section command, as demo below,
Yes, same result here (also in Windows) - running Intersect results in a closed polycurve with two segements (because of the seam), SimplifyCrv makes it into a circle object.
@Olly_Stephens - please run SystemInfo in Rhino and post the results here.
So a little more info first. I took another Mac that didn’t have Rhino on it and installed it. It defaulted to 8.19 and intersection worked fine. I then upgraded it to the 8.20 release candidate and intersection broke. So it’s a new problem with the current release candidate (on mac only by the looks of things).
My systeminfo is attached.
rhino-8-20-mac-sysinfo.txt (12.5 KB)
Yes, it does appear that way, works here on 8.20.25133.14001, 2025-05-13 Windows Rhino.
Hi Olly -
This works fine with the current in-house 8.20 version (8.20.25137.15002, 2025-05-17).
But, from your SystemInfo, it looks like this might be yet another instance of the Intel-AMD Macs problem that we’ve been seeing.
→ RH-87449 Render mesh broke for some mac users in 8.20
I’ve added this thread to that YT for the time being…
-wim
mac intel
can NOT reproduce:
correct intersect result / full circle
Hi Tom -
With AMD?
Please post the full SystemInfo data.
-wim
systemInfo_tom_P_25-05-14.txt (12.8 KB)
Hi Olly -
Just to make sure, could you download the current 8.19 version and run that on your machine to check the result? You don’t need to install / overwrite 8.20, but simply run it to do this test.
-wim
Hi Wim. Yep, can confirm that the current 8.19 version works no problem on my original mac. Intersection is a closed curve which simplifies to a circle.
So that’s same behaviour on both my machines.
For completeness, I’ve attached the system info from that machine too.
macbook-pro-sysinfo.txt (13.5 KB)
Hi Olly-
Thanks again for reporting this.
Just a head’s up: I’m going to send you an experimental build in a PM to test a theory I have about this problem. If you don’t mind, please test that build and reply here whether or not you experience this bug in that build.
-Dan
We are tracking this bug here:
RH-87538 Intersection of two spheres is partial curve not full circle
Hi Dan,
Success - the dujour build you sent me (8.20.25139.12302) works fine.
Olly
Thanks so much for testing that! It verified a hunch we had. We will be backing out the change that caused it and another Service Release Candidate (a more “official” one) should be available soon.
We just published an updated SRC: 8.20.25140.13002. This should fix the issue reported here. Please do me a favor and verify that it does, since we can’t yet reproduce this issue internally (but are working on it).
Thanks again!
Hi Dan. Yep, the newly published SRC works. Thanks for the prompt resolution!
Olly
