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Thread: Material Selection - MDL Select Window

  1. #1
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    Question Material Selection - MDL Select Window

    Hi,

    Just been trying out Iray and have been enjoy my experience until it comes to the materials. I'm very used to how C4D handles textures. Using the content browser window to select what i need and pull them into the scene. Now i might be doing it wrong. But in iray the only way i've been able to get textures in from the vmaterials is Create > Shader > NVIDIA MDL Material > Toggle down. Doing this process for each texture seems wrong to me. Can these be added to the content browser or can multiple ones be selected? Sorry if i'm missing the obvious here.

    My primary use of C4D for work is creating stage sets for events, conference and awards. I will often light a scene with materials that give off light eg. the screen is self. With standard textures i'd select the Luminance channel along with GI Area Light and of course turn on GI in the scene. With iray i've not been able to achieve the same effect of having the screen texture give off light. I've seen some emission textures but they don't appear to work how i was expecting.

    Sorry if some of my terminology is off. I'm self taught so kind of stumble my way through things, but i can see the advantage of iray within my area.

  2. #2
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    Default

    I guess when you say "textures" you really think "materials"?

    If you pull those Cinema material presets from the Content Browser into your scene then they will render with Iray as well, mostly in rather basic quality and with only physically plausible features and parameters supported (because converted to PBR MDL materials underneath). The MDL Select Window was intended to provide similar functionality. Admittedly it lacks several of the convenient ways of working with Content Browser, but we are getting closer. You can, for example, drag and drop a MDL entry directly onto your object. Going straight into Content Browser is also on our list.

    Regarding emitting geometry and textures, this is actually one of the strengths of physically-based renderers like Iray, where GI is not an option but always computed. You can use the luminance channel of a Cinema material to get started, or use an emitting MDL material (like core_definitions::add_emission) to define more illumination properties and assign a texture. You might need to tweak the Exposure on the Iray Camera Tag to adjust to the overall lighting situation.
    Last edited by steve; July 10th, 2017 at 14:56.

  3. #3
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    Default

    Thanks Steve, yes sorry i meant materials, self taught bad habit

    [EDIT] Hi Steve, sorry my below text is kind of NA now. I was looking back over a NAB 2016 Rewind video and notice by comparison my intensity was around 1000, where as the video had an intensity of 2500000. Upping it has given me the light i was expecting to see same with a standard C4D material using 900% brightness. I'm guessing this is where the exposure tag would come in that you mentioned. One other question are Volumteric lights in iray?

    I'm still having issues with getting an object or material to emit light. I've tried both the MDL material and a standard Cinema Material. If i keep it simple, New Scene, Floor and Cube object. C4D Luminance material or MDL material applied to the cube gives me just a flat looking cube.

    Click image for larger version. 

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    What i was expecting to see was a bright cube and light spilling onto the floor. As with the standard rendered with GI enabled. What am i missing :\
    Last edited by DBR; July 11th, 2017 at 17:25.

  4. #4
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    Lightbulb Light-emitting geometry

    Quote Originally Posted by DBR View Post
    I'm still having issues with getting an object or material to emit light. I've tried both the MDL material and a standard Cinema Material.
    Either raise the intensity of your lights or emissions to very high, physically plausible values, or, alternatively,
    decrease the "exposure value" in the Iray Camera Tag to capture more of the subtle light.
    Example scene attached. Left cube with Cinema standard material using luminance, right with MDL emissive material.

    Hope that helps.

    Click image for larger version. 

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    Last edited by steve; July 12th, 2017 at 16:02.

  5. #5
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    Lightbulb Volumetric light

    Quote Originally Posted by DBR View Post
    One other question are Volumetric lights in iray?
    You can do basic volumetric lights with Iray already, by encapsulating the scene into a volume container and assigning a scattering material (a good start would be the MDL core_definitions:thick_translucent). See image. Just uniform scattering at the moment.

    It was discussed already in another thread:
    https://forum.nvidia-arc.com/showthr...lumetric-Light

    Click image for larger version. 

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