How to quick render simple scenes in low res in Blender? - render

I have started using blender to make simple 3d animations, but my laptop will heat up too fast when rendering, and also it takes too much time to render even simple scenes.
I just want to output easily and fast a low res image of the scene, like the ones on the 3D View, but I didn't find any easy nor fast way to do that.
Preferably I will be using cycles.
Can someone help me?

Making renders faster is almost a university degree by itself. Here is a forty seven minute video with some tips.
The simplest step with any render engine is to reduce the resolution. In the render dimensions panel set the percentage to 50% or 25%.
Using 2.79 you can do opengl renders, which is what you see in the viewport. You can enable the display of only render objects to hide all the viewport overlays.
For cycles set the samples low and use the denoising options. The daily builds, which will be 2.81 when released also includes the new denoise composite node that uses Intel's OpenImageDenoise for better results.
If you really want to speed up render times, use blender 2.80 and the EVEE render engine, it is almost realtime and offers amazing results. With 2.80 almost all of the material nodes from cycles will produce the same result in evee and for 2.81 this has been improved even more.

Related

Querying graphics capabilities for deciding whether to apply GPU-intensive effects (through SpriteKit)

I have a game written with SpriteKit which uses a SKEffectNode with blur effect to blur a set of sprites, one of which has a fairly large texture, and which together cover a fairly large area of the screen. An iMac and Mac Book Pro cope quite happily with this but on a more humble Mac Book there is a notable drop in frame rate with the effect node added in. Since the effect isn't crucial to the functionality of the game, I could simply not add the SKEffectNode for machines with less powerful graphics capabilities.
So then the question: what would be a good programmatic check that I could make to determine the "power of the GPU" or "performance when applying texture effects" or [suggest better metric here] and via what API? Thanks for your suggestions!
You'll have to create a performance test using your actual blurring processes and some sample content to get an accurate idea of the time cost of it on each generation of hardware.
Blurs are really weird things, programmatically. A Box Blur can give you most of the appearance of a nice, soft gaussian blur for much less processing cost. A zoom or motion blur (that looks good) is surprisingly expensive, even on strong hardware.
And there's some amazingly effective "cheats" when doing blurs. Because there's no need for detail you can heavily optimise the operations, particularly if the blurs are strong.
Apple, it's believed, does something like this, for example, with its blurs:
Massively shrink the target image
Do a gaussian blur on this tiny image
Scale it back up, somewhat
Apply a cheap Box Blur to soften it
Fully scale back to the desired size
By way of terrible example benefitting from scaling well (with filtering set for good scaling)
This is the full sized image blurred:
And here's a version of the same image, scaled to a 16th of its original size, blurred, and then the blurred image scaled back up. As you can see, due to the good scaling and lack of detail, there's hardly any difference in the blurred image, but the blur takes MUCH less processing energy and time:

Three.js: What's the upper limit for holding 60 FPS on an average desktop?

I'm currently working on a game using Three.js. I've been studying software engineering for four years and have been working professionally on backends for two, but I've barely touched on graphics aside from some simple Unity experimenting.
I currently have ~22,000 vertices and ~8,000 faces according to renderstats.js, and my desktop (above average) can't run it above 20 FPS. I'm using Lambert material as well as a single ambient light, so I feel like this isn't too much to ask.
With these figures in mind, is this the expected behavior for three.js rendering?
I would be pretty sure that is not end of the line and you are probably missing some possibilities for massive performance-improvements.
But just to give you some numbers first,
if you leave everything fancy away (including three.js) and just render an ultra-simple point-cloud with one fragment rendered per point, you can easily get to rendering 10-20 million (yes, million) points/vertices on an average GPU.
just with simple shapes and material, I already got three.js to render something in the range of 500k triangles (at 1080p-resolution) at 60FPS without problem. You can probably take those numbers times 10 for latest high-end GPUs.
However, these kinds of numbers are not really helpful.
Some hints:
if you want to debug your rendering-performance, you should first add some metrics. Renderstats is good, but I'd recommend integrating http://spite.github.io/rstats/ for this (see the example).
generally the choice of material shouldn't matter too much, the GPU is way more capable than most people think. It's more likely a problem somewhere else in the pipeline. EDIT from comment: In some cases, like hi-resolution displays with slow GPUs (think mobile-devices) this might be less true and complicated shader-code can slow down your site, but it might worth be looking at the other points first. As the rendering itself happens off-thread (so you can't measure it's duration using regular tools like the devtools-profiler), you can use the EXT_disjoint_timer_query-extension to get some information about what is going on on the GPU.
the number of drawcalls shouldn't be too high: three.js needs to do a single drawcall for every Mesh and Points-object rendered in the scene and too many objects are generally a far bigger problem than objects with lots of vertices. Reducing the number of drawcalls can be done by merging multiple geometries into one and making use of multi-materials, vertex-colors and things like that.
if you are doing postprocessing, the GPU needs to render every pixel on screen several times. This might as well massively limit your performance. This can be optimized by merging multiple postprocessing-passes into one (I admit, that'd be a lot of hard work..)
another problem could be on the JS side: you should use the profiler or timeline-view from the chrome devtools to see if maybe it's the javascript that is taking too much time per frame (shouldn't be more than 8-12ms per frame). I've been told there are ways to optimize the javascript-performance as well :)

How to get good performance on the gfx card with images larger than the max texture size?

At work, I work with very large images.
I currently do my rendering via SDL2.
The max texture size on the graphics card my machine uses is 8192x8192.
Because my data sets are larger than what will fit in a single texture, I split my image into multiple textures after it is loaded, and tile them.
However, I have found that this comes at a very steep cost. Rendering only 4 textures around 5K by 5K (pixels) each completely tanks the framerate!
Conventional wisdom tells me that the fewer texture swaps the better, but with such large images I've found myself between a rock and a hard place.
One thing I've considered is that perhaps if I were to chunck the images up into many small textures, I could take advantage of culling which would hopefully be a net win. But there's a big problem with that approach - I need to be able to zoom out.
Another option would be to down scale the images. This seems promising as the analysis I am doing on the images do not require the high resolution that the images provide.
I know that OpenGL has mipmapping, but I am inexperienced with OpenGL and am weary of diving into it for a work project. I am not aware of a good way to downscale the images within the confines of SDL2, and for reasons specific to the work I am doing, scaling the images down offline (before I load them) is not appealing.
What is the best approach for me to get the highest framerate in this situation?

WebGL vs CSS3D for large scatter plot of images

I am building a web application which will display a large number of image thumbnails as a 3D cloud and provide the ability to click on individual images to launch a large view. I have successfully done this in CSS3D using three.js by creating a THREE.CSS3DObject for each thumbnail and then append the thumbnail as an svg:image.
It works great for upto ~1200 thumbnails and then performance starts to drop off (very low FPS and long load time). By the time you hit 2500 thumbnails it is unusable. Ideally I want to work with over 10k thumbnails.
From what I can tell I would be able to achieve the same result by creating each thumbnail as a WebGL mesh with texture. I am a beginner with three.js though, so before I put in the effort I was hoping for guidance on whether I can expect performance to be better or am I just asking too much of 3D in the browser?
As far as rendering goes, CSS3 should be relatively okay for rendering quite big amount of "sprites". But 10k would probably be too much.
WebGL would probably be a better option though. You could also take care about further optimizations, storing thumbnails in atlas texture or such...
But rendering is just one part. Event handling can be serious bottleneck if not handled carefully.
I don't know how you're handling mouse clock event and transition towards fullsize image, but attaching event listener to each of 2.5k+ objects probably isn't a good choice anyway. With pure WebGL you could use imagespace for detecting clicked object. Encoding each tile with different id/color and using that to determine what's clicked. I imagine that WebGL/CSS3D combo could use this approach as well.
To answer question, WebGL should handle 10k fine. Maybe you'll need to think about some perf optimization if your rectangles are big and they take a significant amount on the screen, but there are ways around it if that problem appears.

HTML5 Canvas Performance: Loading Images vs Drawing

I'm planning on writing a game using javascript / canvas and I just had 1 question: What kind of performance considerations should I think about in regards to loading images vs just drawing using canvas' methods. Because my game will be using very simple geometry for the art (circles, squares, lines), either method will be easy to use. I also plan to implement a simple particle engine in the game, so I want to be able to draw lots of small objects without much of a performance hit.
Thoughts?
If you're drawing simple shapes with solid fills then drawing them procedurally is the best method for you.
If you're drawing more detailed entities with strokes, gradient fills and other performance sensitive make-up you'd be better off using image sprites. Generating graphics procedurally is not always efficient.
It is possible to get away with a mix of both. Draw graphical entities procedurally on the canvas once as your application starts up. After that you can reuse the same sprites by painting copies of them instead of generating the same drop-shadow, gradient and strokes repeatedly.
If you do choose to draw sprites you should read some of the tips and optimization techniques on this thread.
My personal suggestion is to just draw shapes. I've learned that if you're going to use images instead, then the more you use the slower things get, and the more likely you'll end up needing to do off-screen rendering.
This article discusses the subject and has several tests to benchmark the differences.
Conculsions
In brief — Canvas likes small size of canvas and DOM likes working with few elements (although DOM in Firefox is so slow that it's not always true).
And if you are planing to use particles I thought that you might want to take a look to Doodle-js.
Image loading out of the cache is faster than generating it / loading it from the original resource. But then you have to preload the images, so they get into the cache.
It really depends on the type of graphics you'll use, so I suggest you implement the easiest solution and solve the performance problems as they appear.
Generally I would expect copying a bitmap (drawing an image) to get faster compared to recreating it from primitives, as the complexity of the image gets higher.
That is drawing a couple of squares per scene should need about the same time using either method, but a complex image will be faster to copy from a bitmap.
As with most gaming considerations, you may want to look at what you need to do, and use a mixture of both.
For example, if you are using a background image, then loading the bitmap makes sense, especially if you will crop it to fit in the canvas, but if you are making something that is dynamic then you will need to using the drawing API.
If you target IE9 and FF4, for example, then on Windows you should get some good performance from drawing as they are taking advantage of the graphics card, but, for more general browsers you will want to perhaps look at using sprites, which will either be images you draw as part of the initialization and move, or load bitmapped images.
It would help to know what type of game you are looking at, how dynamic the graphics will need to be, how large the bitmapped images would be, what type of framerate you are hoping for.
The landscape is changing with each browser release. I suggest following the HTML5 Games initiative that Facebook has started, and the jsGameBench test suite. They cover a wide range of approaches from Canvas to DOM to CSS transforms, and their performance pros and cons.
http://developers.facebook.com/blog/post/454
http://developers.facebook.com/blog/archive
https://github.com/facebook/jsgamebench
If you are just drawing simple geometry objects you can also use divs. They can be circles, squares and lines in a few CSS lines, you can position them wherever you want and almost all browser support the styles (you may have some problems with mobile devices using Opera Mini or old Android Browser versions and, of course with IE7-) but there wouldn't be almost any performance hit.

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