Renders take a long time to start.

This is a simple question I was hoping someone could give me some insight on. I have a very capable PC...RTX 4090, Threadripper, 4T, etc. When I start a render it seems like it takes a long time for the iterations to start. It goes through the "gathering" info stage and its getting close to 30 seconds. I know that is not a lot of time, but on every frame of a animation it adds up. The only reason I question it at all is that it seemes like my renders used to start with the iterations almost imediatly. My question is, I have a absolutly massive library now, could this have a bearing as to how long it takes a render to start with the iterations? I know the title is a little confusing, my renders start right away, but it seems like it it takes a long time for them to gather the scene info before the iterations start, and was wondering what factors into that, even simple scenes seem to delay quite a bit. I'm just trying to understand what is going on under the hood a little better. 

Comments

  • If you're doing animations, render one frame out, you don't need to get it to 100%, you could literally stop it at like 20 iterations, as long as there's an image. Do not close the window, just minimize it. Now change it to rendering an image sequence and render it, everything is still loaded and you don't have to waste that time waiting for it all to gather. 

  • crosswindcrosswind Posts: 6,915

    You better check the items in your scene as well as their properties. For instance, if you set high value of Render SubD Level on the figure(s), or if there're complex strand-based hairs,etc. it will take much more time than usual before the 1st iteration starts after you click Render, because a huge deal of high definition geometry data has to be prepared to send to your 4090 GPU... as well as big size texture maps...

  • benniewoodell said:

    If you're doing animations, render one frame out, you don't need to get it to 100%, you could literally stop it at like 20 iterations, as long as there's an image. Do not close the window, just minimize it. Now change it to rendering an image sequence and render it, everything is still loaded and you don't have to waste that time waiting for it all to gather. 

    Thanks for the advice, I can't wait to try this out. If I can get rid of that initial gatering on each and every frame of an animation that will be a huge improvement. Knocking off 30 seconds times 2,000 frames, well I'm not that good at math, but we are talking hours of time saved.  

  • crosswind said:

    You better check the items in your scene as well as their properties. For instance, if you set high value of Render SubD Level on the figure(s), or if there're complex strand-based hairs,etc. it will take much more time than usual before the 1st iteration starts after you click Render, because a huge deal of high definition geometry data has to be prepared to send to your 4090 GPU... as well as big size texture maps...

    You probably hit the nail on the head. As soon as I got my new rig, I did start cranking up the sub D levels whenever I could. As for the hair, I use almost exclusively OOT hair on all my models. I think it looks the best, at least out of what I have found, so that probably does come with a price in terms of geometry. I guess its like everything else, if you want it to look good, you are going to have to pay for it and let it cook.  

  • crosswindcrosswind Posts: 6,915

    surv0101 said:

    crosswind said:

    You better check the items in your scene as well as their properties. For instance, if you set high value of Render SubD Level on the figure(s), or if there're complex strand-based hairs,etc. it will take much more time than usual before the 1st iteration starts after you click Render, because a huge deal of high definition geometry data has to be prepared to send to your 4090 GPU... as well as big size texture maps...

    You probably hit the nail on the head. As soon as I got my new rig, I did start cranking up the sub D levels whenever I could. As for the hair, I use almost exclusively OOT hair on all my models. I think it looks the best, at least out of what I have found, so that probably does come with a price in terms of geometry. I guess its like everything else, if you want it to look good, you are going to have to pay for it and let it cook.  

    Yeah ~ High quality rendering will lead to more time consumption.. There's no other way out because the instance of geometry has to be calculated and prepared each time before you render a frame of your animation... So the only way is to wisely optimize your scene setup.

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