Why Is Blender Lagging In The 3D Viewport?

3D modeling can become one of the most intensive applications for any computer, and as a result of this, you can find the performance in Blender 3D viewport. From time to time can be impaired. So in what scenarios can blend up begin to lag when working in the 3D viewport?

Blender can lag in the 3D viewport when the geometry density of the scene surpasses a certain point. The more geometry in your scene, the more blender needs to calculate. Materials under lighting can also strongly affect viewport performance.

When your viewport begins to lag behind your inputs, it can become frustrating, to say the least. Fortunately, there are several ways in which we can reduce this from occurring by manipulating what we can see in the viewport and how our geometry is displayed in our scene.

The Main Reason Why My Viewport Is Lagging Is Geometry Density

The main reason why your viewport is lagging is going to be the density of your geometry. Depending on the hardware that you are using, you will be able to go up to a certain point in terms of geometric density with for you find Blender begins to lag as you attempt to orbit across your 3D viewport.

This lagging does not affect blender as a whole, merely the ability to navigate in that one viewport. For example, my old setup has an NVIDIA GTX1070 as the GPU. It also has 16 gigabytes of RAM and an Intel 8700 as the CPU.

When working with single objects in Blender, I find the data value of 800,000 is the point at which performance in the viewport begins to lag. When working with a larger scene of smaller objects, this value actually decreases to around 600,000.

These values, by the way, represent the number of triangles on the 3D models. Of course, these will change depending on your setup. If you have a newer set up then you’ll be able to use more triangles in your 3D viewport before you begin to see performance lag.

What does lagging look like you ask? Well, lagging is when you attempt to perform an action such as orbiting around an object, and Blender takes additional time to calculate that action.

Another example could be when you are in edit mode for your objects and then you press the A key to select all of your objects’ geometry. But instead of doing this straight away, the viewport will take several seconds before it selects that geometry.

These are both examples of lagging, and this is perhaps most common when you are sculpting 3D models. When sculpting a single model you will be using tools such as dynamic topology to dramatically increase the amount of geometry density on that mesh.

The Impact Of Lighting And Materials On My Viewport Performance

While geometry is the most common cause of lagging performance in the 3D viewport, equally as likely is the impact that lighting and materials will have on your 3D scenes.

When using texture maps for materials, these will take up significant memory. Memory is a defining factor in terms of both render ability as well as viewport performance. The more memory that your scene takes up, the more difficult it will be for Blender to calculate simple tasks such as navigation and selection, let alone more complex ones.

For Example, If you use textures that are set to a 4K resolution body objects in your scene this. Can cause a lag in few poor performance. However, if you choose to use the same texture at a 1080P resolution, this can actually help to fix the performance issues.

Lighting also affects your viewport performance to a degree. The way the lighting is set up will influence the way that the materials react to it. For example, if you have a scene with many different reflective surfaces, then that means that there is more for Blender to calculate in terms of reflections and lighting.

This increases the total amount of memory required for the scene and also increases the amount of computational time that blender requires when completing each task after.

Using Wireframe Mode While Modeling To Improve Viewport Performance

There are a few solutions to helping prevent a decrease in viewport performance. The most obvious of which is to simply eliminate the factors that cause these issues. In the 3D viewport we have access to certain methods of view.

These viewport methods act as a sort of hierarchical structure for what we want to display in the 3D viewport. By default you will be in solid view. This will display the geometry of your model, but will not display the materials and lighting.

If you find that in solid view performance is lagging, then the problem does not lie with the materials or lighting that you have set up as they are not being displayed in the 3D viewport when solid view is selected.

Therefore, you will need to hide a lot of this geometry from view. You can do this from switching from solid view to wireframe view. The buttons are located in the top corner of the 3D viewport.

By transitioning to a Wireframe view, the faces of your geometry are hidden. You can still see the vertices and edges, but by getting rid of one of the free forms of geometry you can help to very quickly improve your viewport performance while working on your scene.

How My Hardware Affects Blender And The 3D Viewport

In most cases when blender is lagging in the 3D viewports or even when it reaches a point where it can freeze or even crash, the main culprit is likely to be the hardware that you are using with Blender.

While the software can be used to some degree on just about any device that has an operating system like Linux, Windows or Mac, the more intensive your project, the more difficult it will be for low end hardware to be able to function using blender.

When discussing earlier about the main reason for viewport performance decreasing, we mentioned our older setup. That setup we believe to be the minimum for mid tier projects in Blender.

When working with Blender for more simple tasks, then pretty much any device will be suitable so long as it has a half decent CPU and an absolute minimum of four gigabytes of RAM. However, if working with mid tier projects such as a single sculpt, then you will want at least 16 gigabytes of RAM. A modern CPU and a GPU with at least 8GB of video memory.

A lack of video memory is one of the core reasons for viewport performance decreasing in Blender. If you are able to, we recommend at least 32 gigabytes of RAM. As well as a GPU that has at least 10 GB of VRAM. Both of these can help towards the general performance of Blender when working with 3D scenes.

Control Your Geometry Density With Subdivision Surface And Multiresolution

If geometry density is the main cause of your few port lagging, then the solution would be to simply reduce the geometry density. Of course, you’re not going to want to reduce the detail of your models, so there are a few things that we can do here.

The subdivision Surface modifier allows us to control how much geometry that we have based on a foundation, that foundation is going to be the original mesh.

What we can do is ensure that the base mesh is as low as possible in terms of its geometry density, and then use the subdivision surface modifier to add to that detail. We can then use the modifier to define exactly how much of that detail we can see in the 3D viewport.

We have two options with this modifier. The few port detail and the render detail. If you find that viewport performance is lagging, you can set the viewport value here to a very low level. You can then set the render value to a higher level if you think more geometry is required for more detail.

A more complex variation of the subdivision surface modifier is the multiresolution tool. This allows you to add subdivisions and even unsubdivide your model using this modifier.

You can define the level of subdivisions in the 3D viewport as well as when working with your object as a sculpt. While this modifier is more difficult to use, it does allow you for even more control when it comes to the geometry density of your model.

There is a third modifier that you can use to significantly reduce your geometry density, and that modifier is the decimate modifier.

With the decimate modifier you can choose from one of three methods of decimation to dramatically reduce the amount of geometry on your object.

Using this modifier, you do run the risk of losing some of your detail if you go too low with these values. For example, with the unsubdivide method of the decimate modifier, you can use the iteration value to unsubdivide your mesh and reduce its geometry density.

This works very well on objects that have been previously subdivided. However, increasing the iterations too far will begin to result in a loss of detail for certain models.

While the collapse and planer methods of the decimate modifier work very differently. The same issue remains where using these two aggressively can result in a loss of detail.

What To Do If Blender Stops Responding

When working on a project and blend out starts to lag and become unresponsive, the risk of it just stopping or freezing increases significantly. You will know when Blender becomes unresponsive because the entire window will grey out. It will do so while it is trying to calculate a new value. For example, if you were to increase your geometry by using the subdivide tool and set this subdivide value to a very high number like 100.

Depending on the base of the object, this could take awhile for blender to calculate and you may find that it temporarily greys out as it tries to find that value. The main thing to do here is to wait. In most cases blender just needs a little bit more time to find the value that it’s looking for. And so if it becomes unresponsive in this way, just wait until it completes what it’s trying to do.

We like to use the 30 second rule for this. If it takes 30 seconds or more for Blender to calculate something. Then there’s a good chance that it has frozen in the background. At this point, we would probably look to close the software and then reopen it.

If this problem persists when performing certain actions, then you may want to consider UN installing Blender from your machine and then reinstalling it. You may also want to try a different version of Blender as just about every version created is available from the Blender website.

Thanks For Reading The Article

We appreciate you taking the time to read the article and we hope that you were able to find the information that you were looking for. Below we have compiled a list of additional topics that you may be interested in reading based on the article above.

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