gradient ramp setup for opacity

[rodney71]

would someone be so kind as to help me understand how to set up a basic gradient ramp in the opacity channel of an emissions texture node so i can get the effect in this image. i want to be able to control the falloff direction easily and adjust the brightness of the emmissive texture on a reflector card for a product shot...as shown in the modo preview with the bright reflector card in the image.

i appreciate any help in understanding the proper node flow. thanks,
Rod.

[rodney71]

and even more cool would be the ability to control a gradient ramp in both the U and V directions (horizontal and vertical)...probably two gradients need to connect with a mix node or layer node somehow in that case?

[funk]

Hey Rod,

Here's one way you can do it. "Octane Gradient 2 U" controls the gradient on U, while "Octane Gradient 2 V" controls the V gradient. They are both multiplied into a single texture.

This example plugs the combined gradients into the material's opacity (since you asked for it), but I generally plug my texture into the emission node texture input.

The zip includes an lxo and orbx (for anyone who doesn't use modo)

[rodney71]

wow Funk, you're such a gentleman. this is the second time i've run into your helpful input in the past couple days. your node setup looks perfect and i wouldn't have figured it out with all the non-intuitive node process. it'll take some time with tutorials. this is very useful though. your suggestion to plug the output of gradients into the emission node should also work. i've just found in the past that fading to transparent gives added safety on reflective surfaces so that the dark color isn't getting reflected and causing an edge to show. if you place things right you shouldn't see that in this particular case.

again. such a big help and thank you.
Rod.

[funk]

I'm glad I could help

[rodney71]

quick question now, if i may. i've been trying unsuccessfully to copy your node setup to my working file to see how it works in an actual scene. if i try to copy all the nodes in your material override and then switch to my file Modo crashes every time. it seems that isn't the proper way to do it. when i try the suggested method "copy material" in the properties panel of the material override and then pasting it into the material override of my othre scene it seems to bring in extra nodes and changes some of the existing nodes to different versions....reverting back to different transform nodes and gradient nodes etc.

what is the best way of copying over the node setup in Modo from one material to another? seems like these steps should be a lot more straightforward.

thanks

[rodney71]

the two attached images show your node setup and the second is how it changes when i copy and paste the setup on a new material:

[rodney71]

i think i found that i could drag the object over from your file to mine and it came through ok. for some reason last night it wasn't letting me do that and there have been crashes along the way. i'd still be curious as to your recommendation to the best way to move materials from one place to another.

[rodney71]

by the way, here is a raw render of the product shot i was using your texture setup on. fruits of your labor, if you will:

[funk]

I tend to set up every material manually, but you might want to save it as a MESH preset or Octane override MATERIAL preset

MESH preset:
Right click the "card" item in the item list > presets > save, and save this as a "mesh preset" LXL, to a path in your preset browser.
You can then open the preset browser with f6, find your preset and double click it to add your reflection card to any scene (it will load the mesh and octane material)

MATERIAL preset:
Select the override, then click save preset in the octane toolbar (this button actually saves an "assembly preset"). Save it to a path in your preset browser.
When double clicking the preset, it loads the override into the root of the shader tree, so you need to drag it into your material manually.


The copy/paste material buttons actually copy Octane's internal nodegraph, which as you can see, is often much messier that what you create in the modo schematic. I tend to avoid these commands.