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Dannyx

Rendering performance discussion

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Dannyx    0

Good day folks. As a beginner user, I didn't dare start this discussion in the rendering or hardware section, since I didn't want to get bashed with "professional" comments, so once again I'll restrict it to the beginner section.

 

This discussion is mostly about hardware, though it could very well cover software issues. Having a...well, modest PC, it's no surprise that an overly-ambitious C4D project I'm messing with takes an awful lot to render. The "modelling phase" itself goes smooth enough, that is, the program is very responsive and handles well - no lags or anything that would make you pull your hair out. Things start going down the drain when it comes to actually rendering something, which is what all projects have to end in. For instance, to put it into perspective, I use the Interactive Render Region (IRR) a lot to see how textures look "though the eyes of the renderer" so to say, since what you see in the viewport doesn't correspond to the final result and the render time there is just....slow. The end result looks very pleasing for my taste, but I estimated that it would take approximately a week, maybe more, to render what I got going on :)) On a different note, it could be that the time is perfectly acceptable and it's my expectations that are too high. How's around 10 minutes for a single frame sound to you? :| I've got nothing to compare it to.

 

Of course, it's a no-brainer that the more complex of a scene you've got, the render time goes up with it - no question about that. I'm not that much of a noob, but it all comes down to one simple fact: sheer PC power. Say I'm planning to invest in a workstation that's "optimized" for C4D and perhaps other modelling and video-editing tools, what exactly should I be looking out for ? Cores or clock speed ? There's probably no clear-cut answer to that as far as I read. Let's narrow it down even further and maybe trigger some people :)) Intel vs. AMD ? :)) No definitive answer there either, but the price difference IS significant, so if I could get away with a Ryzen as opposed to a CoffeeLake, the Ryzen is significantly cheaper than the Intel and also has more cores....which would be beneficial for rendering as far as I learned, though it's dependent on other factors as well. The GPU I got going on is...decent ? An AMD R9 390...don't know what to say about that. Seems to me that, and I said this before, C4D doesn't use the GPU for rendering as much as it taxes the CPU.

 

On that note, I could be doing something wrong on the software side and not know how to configure it properly for maximum efficiency, so that's another thing worth discussing. I read that some of the resource hogs are stuff like Ambient Occlusion and GI, but in my case I would actually WANT GI in my scene, so I guess I'll have to either deal with it, or give it up - no solution there. Cheers and thanks for any input that would hopefully help me make a decision in the long run...no need to spend millions on something only to realize it's not what you expected and doesn't live up to the hype.

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Rectro    676

Hi

 

Gi is a killer as you say but you can use a large Area light to give a global lighting to mimic GI.  SDS tags set too high will cause slow down as well as Displacement maps.   We need to see the scene or get a idea of how large the scene is.  Optimisation of the scene can certainly help.  Blur reflections, another one to look out for.  You could have your render settings too high where your getting diminishing returns. 

 

Hardware wise for CPU rendering more cores/threads the better, where as modelling, and single core tasks a high clock rate.  Ryzen has shown some serious  Cinebench marks, but dont over look the older intel xeon chips, they make up a nice render farm too.  10min is not that long to be honnest depending on the complexity of the scene and quality, and how many frames you have to do.  You may want o look into another render engine such as Redshift, or Octane but your need a couple a decent GPUs to get the best from that.  What cinebench score is your system getting out of interest?

 

Dan

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jbatista    28

Hi

 

I saw this once (https://www.boxx.com/solutions/media-entertainment/cinema-4d) and it gave me a few ideas how to build an interesting machine. The machine itself it's to expensive but the configuration is something that we can manage to replicate. This machine is best for work since it has higher clock speed and that is good for cinema 4d because it's single threaded .

You can also try to buy some old xeon workstations (hp/dell etc) at ebay that are still powerfull , if you have a limited budget, and they are great in cpu render.

If you can, try some different third party renderers, both cpu and gpu. Most of the time they have demos you can install and test to see wich is best for you. I suggest redshift or octane in gpu (octane has some very good results), but there is also furryball, Thea render, that work on gpu as well . In cpu i really like arnold because it's a very solid and reliable renderer but a little slow. There's also vray that it's a decent all around renderer with good quality results but the plugin has some problems.

 

hope it helps

 

Cheers

 

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Push    4

GI takes a lot of power, ambient occlusion a bit too. Also the type of GI you're using.

One good way of speeding things up is to reduce the Ray, Reflection and Shadow depths which are set way too high as standard, in render settings. Mine a generally sete to 3,2 and 3, where as standard they are 15,5 and 15.

As Rectro says, we can't fully know unless we see your project.

 

I've been using Redshift lately, which is great, even on my single GPU.

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Dannyx    0
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  • Ok, let's fill in some gaps, since I overlooked some details. The CPU I'm using is actually a Xeon, though certainly not the most advanced version. It's an X5460 running 3.8Ghz (overclock). I used to push it even higher than that (to 4 and even 4.23) but it was so unstable it was almost unusable, though I could never pinpoint exactly what was causing the issue, since sometimes it would work just fine, other times it would crash regardless of load/task, so I backed up a bit to 3.8 which seems to be running OK so far. I'm not sure how CineBench works and haven't used it, so I can't answer that, though it would be interesting to try - how do I go around doing that ?


    About the scene: I was thinking of sharing it here, but then again it's probably got many things wrong in it, me being an amateur and all, so you know...slightly embarrassing must admit :)) Though in all honesty I AM aware as you said that there are virtually endless possible scenes you can create, so without seeing the exact one, you can't know for sure...will sleep on it :))

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    DeCarlo    68

    @Dannyx Honestly, there's a bit of a paradox with computer power. I can't remember the exact term, but the idea is that when you have access to more power, you'll be inclined to use more. For example, if you buy a car with better mileage, you'll drive more miles rather than buy less gas. Likewise, if you invest in more computing, you will be less inclined to optimize, and thus end up with similarly long render times.

     

    So while you have tight computing limitations, spend the time to learn all the little things you can do to optimize your scene with minimal impact on the quality. The moment I see a slow render, I start turning off effects. Do a baseline render with nothing on. Then turn on AO and see the impact on render time. Do the same with GI. Lower some quality settings and do an A/B compare in the picture viewer to see what the quality difference is between high and low settings. Lights can also be big culprits, so you can turn on/off different lights to see where inefficiencies are. If an area light is slowing your scene, play with its settings, or exclude objects that are barely being affected by it (but still slowing your render).

     

    Consider using Composite tags to turn off effects on specific objects. (E.g. I had one project with a high-poly cornfield and I turned off reflections for the corn - it offered essentially nothing to my blurry reflections, but the 10,000 high-poly corn plants in a blurry reflection were killing my render times.) 

     

    When you really buckle down and grind through this process, you'll quickly learn where you can cut corners and save lots of render time, and where you are unwilling to compromise on render quality - and that's okay too! (I have one friend who gives me a hard time whenever I share how long some of my renders are, and I always want to say, "yes, but my renders look 500 times better than yours!").

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    BigAl3D    49

    @Dannyx first of all, if you are a Romanian native, I applaud you on your ability to write proper English better than many people that grew up here in the States. ::):

     

    Second, you won't find a better, more helpful place on the web to share your noobie-ness. THIS is the place to ask all those questions and show you mistakes, because you WILL get great advice and you WILL learn and become better. So please, if you can't post the scene, even screenshots will help. We might be thinking of a bedroom scene you're trying to make, but in reality you're making a sports stadium. Very different answers to your questions.

     

    If you're using the built-in engines like Standard, Physical, or Arnold and Corona then a strong CPU and lots of cores are what you need. RAM is always good to get a decent amount, but it won't speed up your renders, just allow you use a lot of large textures.

     

    Since I'm Mac-based, I don't have experience with the GPU engines out there. Don't be shy. Ask away...

     

     

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    Dannyx    0
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  • Yes, I am a native Romanian and I can only thank you back for your praise, what can I say ? :D On a side note, I DO have a major in translation, so it's somewhat of a requirement to have above-average, if not professional English skills! I don't work in the field though, which is why I embraced computers and modelling instead...true, there's no way I can be thinking of a career in the field of modelling at this stage, but you never know. Practice makes perfect. You're also right about the community being very helpful and friendly. I WILL digress a bit here, but it just so happens I also work as an electronics technician (again, the polar opposite of what I should technically be doing) and I often turn to forums for help with various issues. I noticed that locals tend to be very cold, dismissive and even rude in their responses, making them sound way too professional and make you feel bad for asking (even in the beginner section), whereas foreign forums (wordplay :)) ) are MUCH MUCH more friendly and helpful.

     

    Ok, enough digressing, back to the matter at hand. I turned off GI while modelling to speed things up (with the intent to turn it back on when I'm ready to render), so something else is killing it. Lots of cloners - those ARE resource hogs, no doubt about it. I also have blurry reflections going on here and there, so again we have a hog....it's a bank vault I'm trying to create: a corridor leading to a vault door and the interior of the vault itself. The interior has lots of drawers either side (those cloners I mentioned). It's animated too, so the camera moves in from the far end of the corridor, stops where the door is, the door does its thing and opens and the camera moves inside. I'm pretty sure the texture on the door itself is SMASHING it, since if I "disable" the door model, it seems to render faster.

     

    I'm by no means an advanced C4D user, I'm just getting started, so I probably did many things wrong, though I believe in the end I SHALL post my scene nevertheless so you guys can have a look at it....what could possibly go wrong ? :)) I would've done it right now but I'm traveling and don't have access to my local PC. Cheers and thanks. Keep in touch.

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    Vizn    55

    I want to second the advice of @DeCarlo. As an amateur it's easy to want to have all of the detail that real world objects and scenes would have, and to use higher than necessary settings in order to capture those details in the rendered pixels. The challenge then is to learn which modeling/lighting/material details matter and which don't in any given circumstance, and how they impact the rendering engine. This is the art of optimization. Understanding how to optimize early will enable you to take better advantage of the processing power of any hardware later on.

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    DeCarlo    68
    2 hours ago, Dannyx said:

    Lots of cloners - those ARE resource hogs, no doubt about it. I also have blurry reflections going on here and there, so again we have a hog

    You've narrowed it down to what's slowing things. Now you have to start testing how to optimize and diminish that load. 

     

    In your render options, look at "reflection depth" and "Ray Threshold." Depth refers to the number of bounces in a reflection. You've described a room with reflective surfaces on each side. If you've got the default depth of 15, then it's trying to blur 15 reflections onto every single surface. Literally drop this to 1 or 2, and see how it looks (it will run SO much faster). With blurred reflections, you will hardly tell with the resulting render. "Ray Threshold" does a similar thing, but basically when a beam of light dims to the threshold, it stops bouncing around your scene; raising the threshold helps drop really dim rays that won't affect your scene very much. 1% or 2% should help render time with minimal effect on the appearance of your scene.

     

    I'm sure there are additional ways to optimize your lights and materials to the specifications of your scene, but people would need to see the scene or at least screen shots of objects and settings to be able to provide any useful feedback.

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    Dannyx    0
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  • Ok, now we're getting somewhere :D I shall mess around when I get home, see what results I get.

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    Dannyx    0
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  • Here's the render settings at default, with nothing altered. Reflection depth was not at 15 though, it's at 5. I dropped it even lower, to 2.

    Settings.thumb.png.43215a5d176d3a71236dc59afe0e7662.png

     

    Let's look at the scene. Again, probably many things wrong here, but I did it "by eye" rather than "by rules" so to saTy.

    OutsideView.thumb.png.7da75cea5e3f8979f3f0d70b28d7ee26.png

     

     

    Camera starts off at the far end of the corridor, zooms in, door opens and we're in...let's stay outside for now :))

    I found the best trick for creating the corridor without creating enormous planes was to use the "floor" object which is infinite, regardless of its actual size (image 1 viewed from the default camera). I slapped those on either side of the door, using the coordinates manager as much as possible to make it seem as professional as possible. The end result looks like this from the camera's view....

    CameraView.thumb.png.8ccbdb79088bc2413fe99c5bd8cddc44.png

     

    Those ceiling lamps: didn't bother too much with them. The "fixture" itself is nothing more than a poly and I placed a light above it. To avoid using a cloner here I used the "duplicate" feature. The effect looks OK to the untrained eye, though I'm sure that's not how you model a light in C4D...practice, practice, practice. I actually like the slight shadows cast on the ceiling there - that was a bit of an unexpected result, but all the better :D

     

    The door:

    Almost.thumb.png.0ef1a000c0f7e6f470550badba65d9ff.png

     

    It's a print-screen captured from the IRR so that's why it looks pretty awful, just to give you an idea of what's going on. It's not supposed to be black like that - it's supposed to be brushed steel....yeah, whatever, I know, I tried :)) It looks way better when fully rendered, with all the fancy settings "turned on", but again: VERY slow - would take, I estimate at least a week for those 10-15 seconds of animation, it's silly :)) Seems to go slightly faster with just that one change I made, so let's keep going. Yes, I too admit that I'd like to get it to look absolutely gorgeous, but I probably bit off more than I could chew, or rather more than my machine could chew....anyway. Cheers and thanks.

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