Why Does Rendering Take So Long? Details Discussion!

Why Does Rendering Take So LongRendering is an unavoidable process in the world of architectural visualization. Sometimes it can be so annoying to wait for the rendering to finish as you can’t engage in any other work. You can pray all you want to go faster, but the computer works on precise calculations. 

Let us picture a scenario for you. You have a deadline coming up. You are working day & night for the project but didn’t account for the rendering process that much. In the end, the rendering time costs you your project. Is rendering time that much important? 

Of Course, it is. Whether you hate the wait or pray, the time is calculated according to your project. It’s a memory-intensive process that the computer needs to process pixel by pixel. But why does rendering take so long? 

The answer to this question lies within your project itself. There are many reasons that can result in a longer rendering time. You might have too much detail in your work. There can be motion animation involved that results heavily in increased rendering time. 

Let’s discuss in detail how the rendering works in your workstation & what factors contribute to increasing the rendering time. 

What is rendering & how it works?

Before going into the details let’s take a look at how rendering works. In the computer graphics world, rendering is the process of generating two-dimensional & three-dimensional images. It’s like taking a picture of the real-life world, but it’s on your computer. 

From an architectural perspective, it is the process of visualizing the interior or exterior of a project before it goes to construction. It demonstrates the outlook of the project. This foresees how the project might look in the real world. It converts the 3D wireframe models into 2D images with all the photorealistic effects. 

Hardware Side

CPU Specs 

Unlike any other profession, 3D visualization relies greatly on the technology you are working with. Because after a 3D visualizer gets his work done, he needs to wait for the whole rendering process. This waiting period varies a lot depending on what type of CPU you have. 

The CPU works hand in hand with the GPU to process the work much faster. For example, an Intel Core i9 will of course work much better than an Intel core i5. You may have all the skills you need, but if your workstation makes you wait, you have nothing to do here. The faster your CPU’s processing power is, the shorter render times you will get. 

GPU Specs

GPUs have the sole purpose to speed up the processing power of rendering images & videos. Make no mistake. They are not here to replace the CPU. Both the GPU & the CPU work side by side to give you the best results. 

GPU is here to accelerate & streamline your workflow to ensure the best results in a lower time. The more powerful GPU you have, the lower your rendering time will be. But remember that CPU & GPU needs to be working at an equal pace to ensure lowering your render time. 

Architectural Project Site

There are some external factors that weigh in to increase the render time. This one actually discusses the factors within your 3D project. 

Software for 3D render

There is numerous software out there that perform 3D rendering. They process the pixels in their own way. But you can’t question why does rendering take so long in Blender. Or why does it take long on Sony Vegas? 

Every software has its own settings. You need to be aware of that. The truth you are seeking lies within the details of your project process. The software has very limited contribution here. 

Type of Architectural Visualization 

You might think that if you develop any scenery, it should take the same amount of time to process. But no! There’s a huge difference in what type of scenery you are rendering. 

If you are working on an interior visual, then there are fewer elements here to render. But if you compare this with an exterior visual, then your workstation has its hand full. There are much more elements here compared to a confined space of the inside visual. 

The rendering time of an exterior visual can vary depending on what type of render you are doing. You can do a 3D model or a full-fledged CGI. This depends on the architectural designer. But in summary, the amount of elements plays a huge role in rendering time. 

Photorealistic Rendering

Photorealistic rendering allows you to make a digital image on the computer, but it will look like a realistic image. It will resemble the real-life world more. If you are aware of architectural visualization, then this helps clients better understand & judge the work that you are doing. This has become an industry standard for all. 

Naturally, photorealistic images need much more detail than other images. Behind the scenes, your workstation works tirelessly to render such work. On a large scale basis, photorealistic rendering requires a lot of processing time. But if you are aware of the settings, you can shorten the time a bit. 

Reflections of Light on Structural Objects

Working with reflections & refractions is similar to creating your own physics in your work. You are basically playing God to result in the real-world image your clients want. Reflections are a property of light on how they bounce off certain surfaces. On the other hand, Refraction is how light rays go through the surface. 

These two properties play side by side in the real-life world. In architectural visualization, you need to be aware of how your design works with these properties. You will be increasing your rendering time while working with the light rays in your 3D work. 

You need to get the right light settings as it’s essential to represent in front of your client. Having proper knowledge on this matter is mandatory. Otherwise, you will be having much more render time than usual if you don’t have the optimized settings. 

Motion Animations Effect on Architecture Rendering

You know a lot of things as you are reading through this article. One of them should be the difference between rendering a still 3d animation & a motion animation. Motion animations need much more frames to be processed for better animation. 

When you are working with motion in your 3D animations, then rendering time is increased a lot. There is a lot of physics involved here when you bring in motion. This contributes to the increasing of rendering time. 

Shadows Result in Increased Render Time 

In the real-life world, shadows play a vital role. As an architect, you need to showcase the effects of light & shadow in your project. This is a huge part of photorealistic rendering. There are many ways you can render shadows.

Two of the most used ways are depth map & ray tracing. A depth map requires less time as it’s created by casting light at the object. Ray tracing requires much more time as it simulates actual light rays that hit the camera. You need to work smartly as using the wrong method can cost you both to render time & potential clients. 

Architectural Render Settings 

Working with 3D animation tools can get tough. There are a gazillion settings to be aware of when working on them. But when you are playing God, that’s the level of awareness you need for your project. 

But the thing is, this lack of settings knowledge can increase your rendering time to a great extent. Even a small tweak won’t harm your output file but will contribute to decreasing the rendering time of the work. Lack of settings knowledge can really become hectic working on larger projects. 

Output Resolution for Standard Architectural Projects 

This part should be common sense to all you 3D people. The larger the output you want, the more time it will need to render. Once the standard output size was 720×480 pixels. But over the years with the revolution of computer graphics, this size is now 4k or even 8k. 

4k has a size of 4,096 by 2160 pixels & 8k has a size of 7680 by 4320 pixels. You can come to the conclusion that that’s a lot of pixels to process. With the monitor size getting bigger & people shifting to projection screens, 4k & 8k are becoming the norm in the industry. This is a great point to the age-old question, “Why does rendering take so long”


Let’s be honest. No one likes to wait for eternity for their rendering to finish. But if you want to become a better 3d designer, you need to embrace it. Instead of asking why does rendering take so long, you need to be thinking about how I can decrease it to an extent. 

You need to understand where you can save rendering time. It can be tweaking a simple detail or even a simple setting. This quality separates a great designer from an average one. Understanding your design & settings is the key in succession.