Cycles: black things???

Hello, why are there black things on the sides of my glossy​ material?

here are the nodes for it:

Please this is urgent.i have a deadline and its 8 pm at my place and i need this fixed by tomorrow! :frowning:

first instinct says, normals, second says duplicated faces. my actual thoughts say how on earth does he expect us to know the problem when theres no file to look over :frowning:

i would check the material on a default object just to test if it is the material that is giving you problems, it may even just be that you need a lamp around the sides of the object to illuminate those spots

oh i am so sorry i forgot to attach :o

mathproject.blend (1.64 MB)

yeah its a 7th grade math project… :smiley: Are you still there?

add an edgesplit modifier, and set to smooth shading - that kinda helps. also, when previewing, turn the samples down - 2000 is too much to wait for.

bit of a mystery, fiddled around with the textures and stuff tweaked a few settiings took out the collission physics and messed around with the shaders some more no effect

deleted the cylinder, added a new cylinder and re assigned the texture- fixed it, no issues
see if it comes back when you re do whatever the animation was and reattach the camera to the new cylinder, that way you will know where the issue is, unless it was just a duff cylinder in the first place

Thanks so much!!! :slight_smile: i had the preview at 2000 because i watch how many samples it takes for a fine render. then i turn the samples down to the right number. sounds kinda weird but hey :wink:

well i hope it works. good luck with the project

thank you :slight_smile: i will let you guys know how the project went after school.

You need to add some loop cuts around the edges to “tighten” your mesh. Like this:

[CTRL R] with the mouse cursor above your shape. Move around to select where you want to add the loop cut. [Left-click] to enter finer positioning. And another [Left-click] to confirm.

For the top and bottom faces which are Ngons (faces with more than 4 vertices), I used [I] to inset them. You select your face(s), press [I], move your mouse to position the new loop cut and [Left-click] to confirm.

The result:

(Nice material, BTW…)

A little tip: Add temporarily a Subdivision Surface modifier. If your shape loses… its shape, it means that it needs more loop cuts.

Awesome thanks :slight_smile:

? you only need control loops if you add a subsurf modifier. smooth shading will give the proper shape without extra geometry. unless your saying the control loops will fix the black mark issue without having to delete the cylinder?

edit: well there you go. it does seem to clear it up

i added a new cclinder then smooth
and you do get some darks bands near top and bottom

wondering if this is not a bug !
i mean this rendesr better in flat mode then smooth mode!


hey guys, i got a 100/100 on my math project! thanks so much :smiley:

Kaluura, could you post the blend file of that cylinder please? thanks :slight_smile:

well done.

i figure it must be some kind of bug, as when i add a new cylinder and smooth it clears it up nicely

That’s your own blend file. I just changed the size of the render to make the image… but if that’s what you want. No problem.

mathproject2.blend (1.57 MB) (I had to redo it.)

And, BTW, congratulations for “my” perfect score! :p;)

heheheh :stuck_out_tongue: