iray help please / WIP

[Cesar Rullier]

The image above was rendered using A+D materials, it took 3H45min. One of the challenges is the when using the MR exposure control, the preview does not show an enough lit scene for me to make the right decissions in regards to exposure and such (setting) Is there a way to make it render slightly longer?

The main concern is the glass panes on windows. In the above render I had to completly hide the glass (a thin box with a double sided glass A+D material) in order for the sun to shine in and cast shadows. I wonder what I am doing wrong. I have see the in the Autodesk demos they have glass in their scenes.

Here is the Mentalray counter part, it took 1min 12sec. GI+FG
Can I get the same results with iray?



At this point I am starting to question what is the advantage of iray.... at least with other engines you get realtime feedback and they seem to be much much faster. For instance Octane (the only one I have played with).

In case you're wondering the iray machine is
i7 930 + 2 GTX470 GPU

Mentalray render took place on i5 Quadcore (imac) + i7 930 distribured rendering.

[Justin Hunt]

think of iray as maxwell ,its a brute force render, as such slow but easy to use. If you want more instant feed back take a look at the progressive rendering with mentalray. You have to activate it with maxscript. Read up about it in the help files.

If you want fast rendering then stick with straight mentalray or fork out $$$$$ for a Telsa GPU or two

Check out Jeff Pattons blog he give some interesting tips for iray.

jhv

[Cesar Rullier]

Ive read the blog. He used glass and gets light through.... I cannot. I wonder then what he is doing differently.
I did look up the progressive rendering, looks interesting.

[Andrew Lynn]

Honestly I haven't yet seen evidence that iray is a useful desktop solution for arch vis, for the reasons you've noticed - you get to an interior and you realize you're running Maxwell, only on a GPU. You'd hope that since the GPU is soooooo much more powerful than a CPU it can handle Maxwell at a reasonable speed, but there are two flaws in this plan: first, the proposition that a GPU is significantly faster than a CPU is baloney based on a common misunderstanding of how to read the stats that describe computing power, and second, it is impossible to make Maxwell run at a reasonable speed. So if you're good at mental ray you can just run a mental ray render and get it over with, like reasonable people did before nVidia came up with this great new way of making money.

Don't waste your money on Tesla cards. They're just Geforce 470 class GPUs with more RAM. (No, really, a Tesla C2050 or C2070 is a GF100 GPU with 448 threads enabled at 575MHz, with 3GB or 6GB of RAM; a Geforce 470 is a GF100 with 448 threads at 607MHz and 1.25GB of RAM. The current Teslas are underclocked Geforce 470s with extra memory. Run the numbers on what that memory costs the customer and you'll understand why nVidia is so excited about iray technology.) Jeff Patton found that, for scenes that fit into the 1.25GB, a 470 is faster than a Tesla at rendering in iray.

(Yeah, I'm hard on nVidia. I will continue to be hard on nVidia until somebody proves me wrong.)

iray seems more interesting as an enterprise thing, like the guy who was posting a while back who's got a setup to go straight from Revit to a CUDA farm and return renders in near real time. Until the software comes a long way, keep using "compute" as a verb.

[Cesar Rullier]

I thought i posted a reply last night, maybe I forgot to hit "post quick reply" any way, do you know how I can find the threads of this guys workflow?

[Cesar Rullier]

I wanted to update and say that I rendered another scene with glass and it worked fine in iray..... maybe that one scene I mentioned it broken.

[Jennifer O'Connor]

Without seeing he scene it is hard to tell what is going on. Are you using the Unlimited setting for the Trace/Bounce?

[kcpr raffaEl]

I wanted to update and say that I rendered another scene with glass and it worked fine in iray..... maybe that one scene I mentioned it broken.

Hi!

I've figured that with iRay reflectivity of glass affects the amount of pass-through light.

So - the more reflections - the less light inside.

And - in my opinion when you render scene with windows out of Camera visiblity it's useless to use glass in windows - it produces much more noise and I didn't noticed any more realism in scenes...

Take look on my online portfolio http://www.wizualizacje-3d.eu/en - most of scenes there are made with iRay.

Greetings,

kcpr raffaEl

[Cesar Rullier]

thank you. nice work. You are correct, no need to render glass if its out of sight.
BTW do you own the classroom scene?

[kcpr raffaEl]

BTW do you own the classroom scene?

Nooo In portfolio it is only my interpretation of this scene.

The 3D model is open source, avialable on the network, it's called "Maxwell Render Classroom Test Scene".

If I'll find where it is I'll post you a link.