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View Full Version : nasty artefacts in rendering. Help?

rodney71
05-26-2005, 04:37 PM
I'm having trouble with grainy artefacts in an image I want to be clean and smooth.

I am attaching a C4D file for you to troubleshoot as well as the image to show the results. I am getting some really grainy/noisy areas in the render which shouldn't be there as far as I can tell. I don't know what's causing this as there is nothing in the scene that has that appearance and therefore shouldn't be reflecting that way. I've tried variations in texture settings and render settings (like ray and reflection depth) but keep getting these grainy bands refracting in certain areas on the surface.

This is for commercial work (though quite a small job) so y'all are welcome view the file (and hopefully some of you learn something from it) but don't use the model. thanks a lot for any ideas you can suggest.

www.rodsg.com/test/artefacts.zip (http://www.rodsg.com/test/artefacts.zip)

http://www.rodsg.com/test/artefacts.jpg
PetrolUk
05-26-2005, 04:57 PM
It looks like the antialiasing is too low. In the render settings turn the antialiasing min/max up
rodney71
05-26-2005, 05:27 PM
It seems like there must be something else as well. I turned the min setting on the antialiasing up to 8x8. It helps quite a bit but there's still a bit of artefacting. I hate to go all the way up to 16x16. the render time will kill me. maybe i'll render it overnight to see.
artemesia66
05-26-2005, 05:54 PM
as far as i can tell from your file, your reflection depth needs to be at least 10 to get rid of the black, and you need to ramp up your AA--try a small area at 16x, and then knock it back from there.
rodney71
05-26-2005, 06:04 PM
the problem is I like the darker reflections in most of the areas...it adds depth to have the contrast. When everything is light you lose a lot of the form. Aaaaah well. maybe I can't have my cake and eat it too this time. Probably will have to retouch in post unless a better solution comes along.

thanks
artemesia66
05-26-2005, 06:38 PM
i know what you mean. have you tried putting some dark in your reflection map?
elagman
05-26-2005, 07:42 PM
Whoa that is the biggest water bottle I ever seen! Its almost 200" tall. This is something I will never understand about cinema. I thought it was supposed to be "3d for the real world" It was brought up in a thread in the past. Why are peoples models so big? Does it only matter if the proportions are right? Im not trying to be mean I just never understood this.
JamesMK
05-26-2005, 07:46 PM
Just change your units to millimeter and it's 200 mm tall :shrug: One thing that I'VE never understood is why the units would be an issue (unless your into CAD, in which case you would want to use a CAD application instead).
elagman
05-26-2005, 08:21 PM
Ok i see now. I am used to using cad, and if units are different in the settings than what was used to modell it asks if you want to scale model to match current units. Not a big deal. I just seem to strugle creating scale dependant textures on things with small anisotropic scratches when my units are set to inches. The preview does not match up with what I get on my screen.
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05-26-2005, 08:22 PM
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