Why is rendering so compute intensive?

[phillrulz]

Guys, as it says in the title why is rendering so much hard work, im rendering a 800 frame blender model for a forum member on my 780ti via cuda and it slow as a mofo , thats with my 780ti working 90+% usage. Programs like after effects and blender can play the animation fine but when it comes to the export render it takes hours or days in this case, currently i am getting around 20mins per frame at 1080p. if you can preview it so easily why is it so hard to turn it into a video file.

[SAV1OUR]

because rendering uses almost everything on the computer gpu, cpu and ram to help. that's why you see allot of editing rigs with gpus 

[Askew]

because rendering uses both the gpu, cpu and ram to help. that's why you see allot of editing rigs with gpus 

 

wat

[Nineshadow]

Oh...the wonders of Blender.

It took me 8 hours to render this :

https://www.youtube.com/watch?v=ojahzvFRO-c

[phillrulz]

because rendering uses both the gpu, cpu and ram to help. that's why you see allot of editing rigs with gpus 

 

huh that didnt awnser my question at all. i asked why is it so hard to convert it from a model into a video.

[phillrulz]

It goes through making the file, compressing it, and storing it. If it's a large 1080p file, it will take some time. The preview is usually at a lower quality and it's only a short stream.

If you want to watch a preview in high quality in Sony Vegas, you gotta pre-render it which takes some time, but not too long because it only goes through the process of rendering and nothing else. Same principle applies.

Yea when you use ram preview it does lagg a little but obviously nothing like rendering, i guess its alot lower res and framerate

 

80 frame video is 1.8mb currently.

[phillrulz]

Oh...the wonders of Blender.

It took me 8 hours to render this :

 

 

imagine if you used your CPU ahahah months

[Askew]

Yea when you use ram preview it does lagg a little but obviously nothing like rendering, i guess its alot lower res and framerate

 

80 frame video is 1.8mb currently.

 

Yes, it's just a preview it only does a small fraction of the amount of processing, normally there is an option in the software for the detail level/size of the preview.

[TheKDub]

Oh...the wonders of Blender.

It took me 8 hours to render this :

https://www.youtube.com/watch?v=ojahzvFRO-c

 

Were you using a toaster to render it?

[Nineshadow]

Let me explain this to you...

Games manage to play at 30-60fps because there's a lot(and I mean a huge lot) of fakery involved.However,it's most of the time barely noticeable.

For example,a lot of games use texture baking.When shadows aren't dynamic(they don't move), it's very common to simply "bake" the shadow onto the original texture of the material the shadow was projected upon.

 

Also, 3D renderers have to calculate a lot and a looot of stuff.Just think about it...reading the 3D world,applying textures,shading,projecting into view/camera space(2D) view,post-processing,etc.Heck,it even calculates light bounces.

And in video editing...you have to calculate each pixel for each frame(which can get very very complicated).

 

It's so intensive because it simply is an intensive task.

 

A lot of RAM is being used in programs like After Effects,for example, because when you preview a certain portion of your work,that preview gets saved into your RAM so you can access it at any given time.

 

Given the fact that the work 3D renderers do is very similar to those of gaming GPUs, obviously using your GPU for that would be more effective.I mean...just try and play games with your CPU if you can.

[Nineshadow]

Were you using a toaster to render it?

No.I had to render at 800 samples per frame or else there'd be too much noise.

And I had around 90 frames so...

(I fast-forwarded it because it was too slow)

[Nineshadow]

imagine if you used your CPU ahahah months

Oh...I was rendering a very nice animation once.

Gave up after 2 days.

[phillrulz]

Let me explain this to you...

Games manage to play at 30-60fps because there's a lot(and I mean a huge lot) of fakery involved.However,it's most of the time barely noticeable.

For example,a lot of games use texture baking.When shadows aren't dynamic(they don't move), it's very common to simply "bake" the shadow onto the original texture of the material the shadow was projected upon.

 

Also, 3D renderers have to calculate a lot and a looot of stuff.Just think about it...reading the 3D world,applying textures,shading,projecting into view/camera space(2D) view,post-processing,etc.Heck,it even calculates light bounces.

And in video editing...you have to calculate each pixel for each frame(which can get very very complicated).

 

It's so intensive because it simply is an intensive task.

 

A lot of RAM is being used in programs like After Effects,for example, because when you preview a certain portion of your work,that preview gets saved into your RAM so you can access it at any given time.

 

Given the fact that the work 3D renderers do is very similar to those of gaming GPUs, obviously using your GPU for that would be more effective.I mean...just try and play games with your CPU if you can.

Nice explanation thank you. This is what i wanted

 

No.I had to render at 800 samples per frame or else there'd be too much noise.

And I had around 90 frames so...

(I fast-forwarded it because it was too slow)

 

Im only rendering for this guy at 100 there is a bit of noise but heck im not spending hundreds of hours without gaming :L can upload a preview if you like.

[phillrulz]

Oh...I was rendering a very nice animation once.

Gave up after 2 days.

 

this is 24 hours work 81 frames however that video i would say i less as its supposedly 24fps

[Kingofpants]

Previews take shortcuts and skip over parts that make the video look nice.

Rendering needs a lot just raw computing power to Push out a completed frame that's properly completed.

Imagine rendering this scene

Crumbling World of Crayons (SmallLuxGPU, Blender…:

Your algorithm has to take into account lighting, Every single voxel, Physics , reflection , light scattering , Textures , Materials the voxel is made out of, Air current, Friction etc. It's tough work.

[Nineshadow]

this is 24 hours work 81 frames however that video i would say i less as its supposedly 24fps

Oh,pretty good.

[LOLZpersonok]

This makes me so fearful for what I hope to do in the future, which is to add 3D CGI effects into live action film. 

 

My HP Envy will not be used for this purpose, I'm planning on building an i7-4790K based system to play my games and to possibly do this compositing in the future. My HP Envy, for example, can take 5-8 hours to render a 20 minute 1080p video with the highest quality settings and cuts in the video using Sony Vegas Pro 10. Obviously, this will be vastly improved on an i7-4790K, as my HP Envy has a measly AMD A10-4600M APU and 8GB of RAM, which will be holding it back. 

 

But based on what other people are experiencing in doing this different rendering makes me worried that my i7-4790K (future) build will not be adequate for this purpose, which will be to composite 3D CGI into live action. I want to make a movie so bad, but I fear that rendering will take unfeasible amounts of time. Scary.

[eLucid]

Guys, as it says in the title why is rendering so much hard work, im rendering a 800 frame blender model for a forum member on my 780ti via cuda and it slow as a mofo , thats with my 780ti working 90+% usage. Programs like after effects and blender can play the animation fine but when it comes to the export render it takes hours or days in this case, currently i am getting around 20mins per frame at 1080p. if you can preview it so easily why is it so hard to turn it into a video file.

You're rig in your sig is intended for gaming only, that's why it's taking so long. If you're doing a lot of 3D rendering then you need to invest in a workstation oriented build. IE, an AVID-Dual Xeon-2xFireGLw7000.

 

I'm going to take a guess here, you don't do a lot of 3D rendering, correct?

Edited September 3, 2014 by eLucid