Hello there,
I am a beginner in the 3D world, and recently started my journey with Rhino3D. When practicing Boolean difference on very simple shapes (cube and sphere) I came across something new to me when doing the zebra analysis. When performing the Boolean difference and nothing else, I get straight zebra curves from the top view (as I should). However, when applying a fillet to the edge, the zebra curves start to get divided in the middle to form what seems to be 2 circle halves.
From what I gathered through my research, I was told to not use Fillets, but Blend Surface instead in order to get a higher continuity. However, I tried the Blend Surface tool with Curvature, G3 and G4, as well as tweaking the parameters, but nothing seems to help when trying to create a smooth transition from the cube to the spherical shape without creating the 2 circle halves. I also 3D printed a sample (attached)
to see the effects it would have in a physical item, and you can clearly see the reflection of the circle halves.
Is it simply no way to eliminate 2 circle halves? Or am I missing something? I have attached a file with a couple of tests I’ve done (in Rhino5 and Rhino7). edge tests_help_Rhino5.3dm (1.8 MB) edge tests_help_Rhino7.3dm (1.8 MB)
Please let me know how to solve this!
Thank you in advance,
V.
As I explained to you on Reddit, nothing is “wrong.” No amount of smoothening the fillets is going to eliminate the reflection pattern you see. It’s the product of the reflections on the shape!
And for crying out loud don’t listen to anything anyone tells you on Reddit except me and one other guy there, the rest are children who couldn’t 3d model their way out of a wet paper bag and clowns offering such terrible advice it seems to be deliberate trolling.
Hello Pascal,
To me, it seems to be a ‘weird’ or ‘abnormal’ type of reflection. I can’t think of any other concaved shapes or objects that have similar type of reflection - that’s all.
Hello- well, zebra is not a reflection. It way well be that a true reflection would be the same, I don’t know, but zebra is not intended to reproduce an accurate reflection, it is a false color map to help evaluate continuity and flow of surfaces…
It’s not weird or abnormal. What do you think it’s supposed to look like, straight lines from every angle? It’s a rough approximation of being in a dark room where all the walls and ceiling are lined with fluorescent tubes, what they use to check the quality of car bodies. Obsessing over what the (fake) reflections look like on a form made up of all basic shapes and a fillet is pointless, it’s for evaluating actual freeform geometry that will be smoothly finished.
Zebra is similar to, but not the same as, the reflection of parallel lines on planar surfaces. In this example of a cube the zebra stripes are curved even though the faces are planar.
Hello Jim,
Thank you for taking the time to reply to me on Reddit and here. As a beginner and limited knowledge on the matter, it can be difficult to know who to listen to. I did take the comments and tips in and saw for myself that they did not help, but I did learn new things along the way. Though, to rule out any possible “children and clowns” from Reddit, I decided to post here too.
You can avoid the 2 circles with zebra by having no inflection points (all curvature facing the same way).
If you have more inflection points you will get more that two concentric circles zebrax.3dm (1.4 MB)
