Noob question about iray
marcoprivat
Posts: 0
I'm new to DAZ. I used Poser in the past before i paused for a few years and was always pleased with my render-results. Now i would like to start again and because DAZ provides a wider and more advanced spectrum of content i woul give it a try. I was impressed of all the fantastic shots made with iray so i gave it a try to myself.
But it is verry anoying that the renders take so much time to complete a single scene and even after a couple of hours i get still noise on my pics. Taht really disappoints me. Of course iray looks more real than 3Delight, at least for me. But it also needs a lot more of time to complete.
So i know there a many topics about render time and how to decrease them on this forum and arround the net. But i like to ask some questions about specific things about iray settings.
The first of all is about the advanced options in the iray render settings. there i can choose the Hardware for Photoreal and OptiX. My question about tis option: what do i need to activate? All of the devices, CPU and GPU? And need i do it for both, photoreal and OptiX?
Oh, my HW is a Intel i7 with 3.6 GHz, 16 GB of DDR 3 and a GTX 960 with 4 GB DDR 5.
Next question leads to the Editor -> Optimization in Iry render setting. There i can switsch between Speed and Memory for Instancing Optimization. So what ist the better deal and does it affect the render time? And when should i set the Caustoc Sampler On and when Off?
Now about filtering. Some ppl say Noise Filter On to reduce Noise on your Picture other say it doesn't matter. And also, waht are the best Pixel filter?
Another important question to me is about the Rendering Quality Enable option. I often hear that you can set it Off to reduce render time. But i see no change. And does the Render Quality factor only take eefct if i Enable Render Quality?
Sorry about that spudi questions, but i belive iray is a verry great thing to let pics looks more real. But on the other site there are to many option and i guess bno one have the time to experiment with all of them to finde good settings because of the render time.
So how can i set iray to make crispy pics without spending hours. because not ever one has a second high end PC where you can import your scene just to render them. And every time i start rendering i can't do anything else.
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Comments
One obvious question is what is in your scene, and how are you lighting it? I supect, from the tiem taken, that you may have an interior and the lighting may be just the HDR - otherwise, if you are enabling the GPU, two hours sounds very slow.
It's a bought scene called Cozy Bedroom with some furnishings including 3 Lamps. There are 4 different sets of daytime and i used the sun set. I turned on the 3 Lamps but the mainlight comes from the background.
I have enabled both, CPU and GPU in Photoreal and OptiX. But if i understand right iray is using the GPU of my graphics card? So i wonder why is my CPU load at 99% while rendering the scene? And why it takes so long to complete?
I tried to reduce the Max Samples to under 1000 and the render time was of course just a few minutes. But the result was verry bad. And even if i set it up to the default of 5000 my pic looks still noisy.
Right now i run it again with Max sample 15000 and the max time to 6 hours. After almost 4 hours now i'm at 22% progress and 2055 iteration.
I attached a picture of my last render. I took more than 2 hours to render. There you can see all the disturbing noise especially at the windows frame, the wall next the window and also on the skin of my figure.
Ok i checked the log after the render was finisched. I made a mistake when i said i seted the time up to 6 hou. It was just 5. :)
In my log i see this
If understand in iray the graphic card will be used for rendering and if there is no compatible card it will fall back to cpu? But my GTX 960 matches the requirements but even then is iray using the cpu and that leads to a high load. Why? And why is ther only so less VRAM allocated if my crad provides 4 GB? In task Manager i can see that Daz is using almost 6 GB of my RAM while render a scene.
And also what about the Max Time? I set my render to 15000 Max Samples but if the time is exeeded the render will stop.
And as you can see the CPU processed only a quarter of all the iterations but used 99% load and seems the render time not to accelerate.
So makes it more sence to disable CPU in iray Advanced Hardware Setting totally? And if so, will it speed up the render time? And if i really whant to render with 15000 samples in hope to get better results, is there a way to set the max time to infinite?
How much, if at all, the CPU helps seems to depend on the scene and the system -the same goes for OptiX.
I don't have that set, but interiors can be tricky - especially if there are a lot of reflective/shiny surfaces - one thing that may be worth trying, in the Editor tab of Render settings under Optmisation, is setting the Max Path Length to a positive number (-1 means no limit) - that may help by limiting the number of times a path can bounce from one surface to another. However, it needs to be at least 6 to properly render the eyes so there's a limit to how low you can go - try soemthing like 8 and see if that has any discernable effect, for good or ill.
FWIW, I have found that Max Path Length = 11 is about as high as you need to go. As Richard said, I wouldn't go below 8, though 8 may work for almost all scenes.
Sorry for my late response.
Hm. I tried to set Max Path Lenght to 8. But it feels for me that it now takes even longer as with the default value -1.
Also the Max Samples option seems to me pointless if i leaf the Max Time at 7200. Because it will stop if the time is over regardless if the Max Sample reached or not. 60 or 90, or even 120 Minutes would be OK to me if the render was finished. But it never will in this "short" time. :(
I guess iray will provide verry clear render but at cost of a large amount of time and resource. And that can't be really the goal?
Why does the render take so much time and even than they are not as aspected? Are there no guidelines to twaek iray setting for acceptable results?
The "Help" about iray provided by DAZ delivers only a verry short description for some of the availible options. Is there may be some where a place where i can find more information about using iray more efficient?
Because right now it is verry frustrating usinig iray, Not every one can buy 3 or more PC and the iray Server to build a Render Farm just to speed up the work.