OTOY Forums

hi there

Im using the octane plugin in cinema 4d. I'm currently struggling with a problem i cant find a solution for:

I have two materials combined with a mixed material. one of them is a specular material with all the stuff i need. the other one is a diffuse material in which i only use the emission channel, since there is no emission channel
for the specular material. for this setup i need displacement, so i placed a displacement map into the "use displacement" channel in the mix material. but as soon as i do that, the light emission doesnt work anymore...

Is this a limitation of octane or am i missing something?

would be so great to hear from you.

cheers

Hi,
probably you have the opacity of the diffuse emitter at 0, this destroy the emission.
But you can have a specular material with emission without mixing
Here is the two methods: At the left, a single specular material with scattering medium and emission, on the right a specular material mixed with a diffuse material. Both versions have the displacement active.
Here is the scene: ciao beppe

hi bepeg4d

thanks a lot for your reply. this helped a lot!

i used the texture emission in the channel which didn't work... or am i missing something too there...?

but the blackbody emission with a texture assigned works just fine.

to explain what i'm doing if you're interessted:

i modeld, textured, uv unwrapped a jellyfish tentacle in zbrush. after i generated color, displacement and normal maps i brought everything over to c4d. the idea is to have a light puls that moves downwards from top to bottom of the tentacle. so not the whole tentacle starts to emitt light, its a light that travels through. so one solution i have right now ( after your great tips! thanks a lot for that!) is to bring in an animated black/white texture into the opacity channel. with the blackbody emission on, this should work like a charm. but then i can only drive the color of the light via the temperature setting, right?

can i drive the color of the light with a texture emission? i think so, right? i tested that but it doesnt seem to work with the displacement on in the mixed material..

i would be super happy if you could help me but i would also understand if you have better stuff to do than explaining me all that..! its not that i'm not trying to figure out all that stuff by my self...

have a nice day

Hi,
very interesting project you have! When ready, I would like to see the final result if possible
For coloring the emission, you can use a blackbody node with 6500k temperature, or simply use a Texture emission node, and use in the texture pin an RGB or Gaussian Spectrum node.
Here is the same scene as before with the wavelength animated on both: ciao beppe

hi beppe

well, it will take quite a while because this tentacle, as you might guessed, is part of a jellyfish, which is fully rigged and is part of a short movie i'm working on... but once the jellyfish is done i would love to get some feedback!
if you have freetime and you are bored and dont need money you could help me?? hehe

Thank you so much for all your help! i'm on a good track now.

cheers

fred

I'm very curious, can't wait to see the rigged jellyfish in action
No so much free time in this period, but if you get stuck, don't hesitate to drop a line here
ciao beppe