Home » How do modern game engines achieve real-time rendering vs Blender’s “slow” rendering?

How do modern game engines achieve real-time rendering vs Blender’s “slow” rendering?

Solutons:


Real-time rendering, even modern real-time rendering, is a grab-bag of tricks, shortcuts, hacks and approximations.

Take shadows for example.

We still don’t have a completely accurate & robust mechanism for rendering real-time shadows from an arbitrary number of lights and arbitrarily complex objects. We do have multiple variants on shadow mapping techniques but they all suffer from the well-known problems with shadow maps and even the “fixes” for these are really just a collection of work-arounds and trade-offs (as a rule of thumb if you see the terms “depth bias” or “polygon offset” in anything then it’s not a robust technique).

Another example of a technique used by real-time renderers is precalculation. If something (e.g. lighting) is too slow to calculate in real-time (and this can depend on the lighting system you use), we can pre-calculate it and store it out, then we can use the pre-calculated data in real-time for a performance boost, that often comes at the expense of dynamic effects. This is a straight-up memory vs compute tradeoff: memory is often cheap and plentiful, compute is often not, so we burn the extra memory in exchange for a saving on compute.

Offline renderers and modelling tools, on the other hand, tend to focus more on correctness and quality. Also, because they’re working with dynamically changing geometry (such as a model as you’re building it) they must oftn recalculate things, whereas a real-time renderer would be working with a final version that does not have this requirement.

The current answer has done a very good job of explaining the general issues involved, but I feel it misses an important technical detail: Blender’s “Cycles” render engine is a different type of engine to what most games use.

Typically games are rendered by iterating through all the polygons in a scene and drawing them individually. This is done by ‘projecting’ the polygon coordinates through a virtual camera in order to produce a flat image. The reason this technique is used for games is that modern hardware is designed around this technique and it can be done in realtime to relatively high levels of detail. Out of interest, this is also the technique that was employed by Blender’s previous render engine before the Blender Foundation dropped the old engine in favour of the Cycles engine.

Polygon Rendering

Cycles on the other hand is what is known as a raytracing engine. Instead of looking at the polygons and rendering them individually, it casts virtual rays of light out into the scene (one for every pixel in the final image), bounces that light beam off several surfaces and then uses that data to decide what colour the pixel should be. Raytracing is a very computationally expensive technique which makes it impractical for real time rendering, but it is used for rendering images and videos because it provides extra levels of detail and realism.

Raytracing Rendering


Please note that my brief descriptions of raytracing and polygon rendering are highly stripped down for the sake of brevity. If you wish to know more about the techniques I recommend that you seek out an in-depth tutorial or book as I suspect there are a great many people who have written better explanations than I could muster.

Also note that there are a variety of techniques involved in 3D rendering and some games do actually use variations of raytracing for certain purposes.

Related Solutions

Performance issue with this code [closed]

In short: You should create,open,use,close,dispose Connections where you're using them. The best way is to use the using-statement. By not closing the connection as soon as possible, the Connection-Pool needs to create new physical connections to the dbms which...

Compare a pointer to an integer in C [closed]

Here's what I think you meant to post, it still doesn't compile though, since you can't compare a pointer to a char /* *Description: Construction of a social network */ #include <stdio.h> #include <strings.h> #include <stdlib.h> #define SIZE...

Autocomplete json in textbox

If you are using jQuery UI, the jQuery documentation on autocomplete is straightforward. Put your array as the source: and it should work automatically. IMHO, You seriously need to spend some time for googling and looking into the documentations. jQuery UI...

having all my scores and names in one big array

You need to initialize your array outside of your loop: name_arr = [] while int(students)>int(student): name = input ("what is your name ") score = input ("what is your score ") student = student + 1 name_arr.append(name) name_arr.append(score)...

pacman “exists on filesystem” error

After pacman finally deprecated the --force option and made the surrogate --overwrite option work as expected, the following usage pattern should be noted. A command to reproduce the --force option that blindly overwrites anything that conflicts is this: sudo...

How to determine the maximum number to pass to make -j option?

nproc gives the number of CPU cores/threads available, e.g. 8 on a quad-core CPU supporting two-way SMT. The number of jobs you can run in parallel with make using the -j option depends on a number of factors: the amount of available memory the amount of memory...

Number of Nearest ‘True’ in a matrix or list of list

Definitely not the best way to do it, but it's one that works: import numpy as np mas1 = np.array([[True, False, True], [ False, True, True], [ False, True, False]]) mas_answer = np.ndarray(shape=mas1.shape) for i in range(mas1.shape[0]): for j in...

Trying to display Json data from a web url into a table

You can take this json and put it in the loop through length of the json and show data into the table. This is how i solved it <?php try{ $url="the json url goes here"; // path to your JSON file $data = file_get_contents($url); // put the contents of the...

View v is unreachable statement

Anything else is written after the return keyword it's unreachable. Remove return super.getView(position, convertView, parent); from the first line of your function. This is a warning, telling you that static analysis of the code shows that some of your code...

index out of range but is in fact in range [closed]

Well try to debug your code by yourself first. Anyhow for your question Why is this happening? : It gives you error in postCode = split_address[4] because your list has 4 elements 0,1,2,3 and you are accessing the 4th element which is not present.. you don't...

Ubuntu update error: “waiting for unattended-upgr to exit”

I would first try a softer way. Stop the automatic updater. sudo dpkg-reconfigure -plow unattended-upgrades At the first prompt, choose not to download and install updates. Make a reboot. Make sure any packages in an unclean state are installed correctly. sudo...

how to Styling classes with the same name in a file css [closed]

You need to use :nth-of-type(n) selector. // For First Right Class Div #container .right:nth-of-type(1) { } // For First Left Class Div #container .left:nth-of-type(1) { } Hence for every div you need to change n value. Your question is extremely unclear but I...

Java – different parameters resulting to different outputs

What I think you're trying to achieve is that when you call your method "horn" with some parameter it has to either use "Beep!" or "Boop!". First of: void horn(a,b) Is not a valid function signature in Java, in a java function you always have to specify what...

Cannot use method returned value into another method

Using @super's suggestion and a little warning fixing. The two important changes are in the line as suggested by @super: printf("r=%.3f; phi=%.3fn",distanta(),phi()); The variables 'r' and 'unghi' are both variables local to member functions and cannot be...

Class has no member speak? [closed]

void::speak(); //THE GLOBAL SCOPE HAS NO SPEAK It's interpreting this as void ::speak() where leading an identifier (a name) with :: indicates to C++, "Look in the global scope of all names". :: is the "scope resolution operator" In the header file, you should...

Convert code with multiple lines into one line

Read the docs! A simple statement is comprised within a single logical line. Several simple statements may occur on a single line separated by semicolons. Search Stack Overflow! How to put multiple statements in one line? Or google, to find converters for more...

How to POSITION my Marker to Always Follow the Slider-Handle?

Youc can set a position to image using Jquery See fiddle //set a begining position to img var slider = $(".slider")[0]; var sliderPos = slider.value / slider.max; var pixelPostion = slider.clientWidth * sliderPos; $(".img").css("left",pixelPostion-7 + "px");...

css nth-child() check board pattern [closed]

This is pretty simple, as the pattern is repeated over 2 rows of 4, you just need to apply styles to 8n + i for the chequered pattern: .flex { display: flex; width: 400px; /* width of four squares */ flex-direction: row; flex-wrap: wrap; } .square { width:...