In this article we will focus on the viewport overlays in Blender. The goal is to display the data we need as we work on our scenes while not getting the viewport cluttered with too much information.
We can access viewport overlays and gizmos in the top right corner of the 3D viewport. Overlays are visual ques and guides that help us know what we are looking at and how our blender scenes are structured.
This article is also closely related to my article on viewport shading modes.
Related content: Blender viewport shading guide
Now, let's look at how overlays can help us as we work in Blender.
When talking about overlays we refer to graphical elements in the 3D viewport that is displayed on top of the underlying viewport shading mode as guides to help us understand and orient in our scenes.
Overlays can help us understand the data we are looking at in our scene. A few examples of overlays are directions, object types, scale and size of our world and objects.
We can toggle overlays on or off by going to the overlay button in the top right corner of the 3D viewport. Just next to it is the dropdown menu where we find all overlay settings. This is a dynamic menu that changes depending on what mode we are in.
Some overlays are only available in certain modes while others are common for all modes. The overlays in object mode are generally available in all modes, while some settings are specific for one mode or may even vary slightly between modes.
For instance weight paint mode has two extra settings in weight paint mode but one of those is available in edit mode. Therefore, it is a bit tricky to just go through each setting for each mode. Instead, we focus on object and edit mode and I will try to point out any differences for the rest towards the end.
The features we are looking at here is available in edit mode in addition to object mode. But edit mode has a lot more overlays, so we will cover the common ones first and then go to the edit mode specific overlays below.
In this section we find features related to the viewport itself. You can think of it as the highest level category. First we have the grid, floor and axis settings.
The grid refers to the background grid we see when in orthographic view. That is when we press 5, 7 or 1 on the number pad for instance. This is grayed out when we are not in orthographic view but we can still toggle it and the grid will comply once we are in orthographic view.
A setting related to the grid is subdivisions just below to the right. This is grayed out as well and doesn't change the subdivision of the grid. This is because by default we are using the metric unit system in Blender. With the metric system the grid subdivisions will always be 10.
To change the subdivisions we have to first go into the properties panel and find the scene properties tab. Here we can find the units section and change the unit system to none.
This will use "Blender units" as it's default measurement, and we can now change the subdivisions.
Next we have the floor checkbox. This toggles the floor we see in perspective view on or off. We can scale the floor and the grid together with the scale slider.
By default, the grid is divided into 1x1 meter. The scale value is a multiplier. This means that a scale value of 2 here each square will represent 2 real world meters.
This also affect snapping when it is set to increment and absolute grid snap is turned on.
The axes will toggle the X, Y and Z indicators the meet in the center of the scene. By default, only X and Y are turned on.
Next we have a handful of checkboxes to toggle different types of information.
Text info gives us the current view information along with the currently selected collection and currently active object in the top left corner. The active object is the last selected object and have special meaning in many operations in Blender.
As of 2.90 and beyond there is also a statistics checkbox that toggles basic statistics of our scene geometry. In earlier versions of Blender these numbers were only available in the status bar at the bottom of the interface.
Next we have 3D cursor and annotations. These toggle the view of the respective feature.
The annotation tool can be found close to the bottom in the toolbar on the left side along with the measure tool. We can use this feature to draw notes and comments for ourselves directly on top of the 3D viewport that won't be rendered.
In material preview shading mode we also have an HDRI Preview checkbox. This will render two spheres in the bottom right corner so that we can preview the reflections and shadows from the built-in hdris.
The HDRI Preview checkbox is actually the only difference I have been able to find between a rendered viewport mode with Eevee and material preview mode. According to the manual though, this is supposed to be available in rendered viewport mode as well.
External content: Blender manual viewport overlays
The objects section zoom in a bit and affects object related guides and visual ques. We have seven checkbox toggles here.
The extras checkbox will hide or show objects that only have a placeholder in the 3D viewport but isn't actually a physical object. Things like, lights, cameras and empty objects fall into this category.
Relationship lines shows what objects are parented to other objects by displaying a dotted line. If you are utilizing parenting these lines can really clutter up your interface, but it can also be useful to be able to see relationships directly in the viewport. Therefore, the amount of parenting going on will decide if you need this or if it is getting in the way.
Next we have outline selected. It turns on or off the outline of selections. In essence, we can't see what is selected in the 3D viewport if this is turned off. However, if we have a massive amount of objects it can be a real performance hit to draw all those lines if we make massive selections. So in order to gain a bit of extra performance when re make these huge selections we are able to turn this off.
Bones doesn't give much of a surprise either, it just hides and shows bones that are part of an armature.
Motion paths is the path something animated takes through an animation frame by frame. It can be very useful for animators to get a good view of the full path of an animated object through multiple frames. Here we just toggle the view of them overall. But to see motion paths in the first place we go to the object properties panel and find the motion paths section.
Here we can press calculate to calculate the frame range specified. In the display subsection we can more granularity change what data we want to see for our motion paths.
The origins checkbox will hide or display origin points for objects that are selected while the origins(all) will display all origins that are not selected as well while checked.
Here we have three more checkbox toggles to explore. The first one is wireframe. In wireframe viewport mode we only have a slider that decides the angle an edge need to be in order to be visible in the viewport. However, in all other view modes there is also a checkbox to turn it on or off.
This allows us see both solid shading with wireframe on top or even the rendered scene with wires rendered on top.
Face orientation is interesting because when enabled it will show the front side of each face in blue and the backside in red. This way we can quickly scan our scene for faces that face the wrong direction. Making it easy to check ourselves for faulty geometry.
When we enable motion tracking a few more settings are displayed. These are:
These are quite self-explanatory. Camera path show a line where the camera travels through the shot. The markers will be shown using some empty type display, and we can change the size of these trackers.
We can also choose to display the tracker names so that we can identify them easier between different editors.
Now we will cover the settings that apply to edit mode for mesh object. There is another much smaller set of overlays available for curve objects. We cover those at the end of this section.
In mesh edit mode we can show and hide different markings and adjust how edges and faces are shown. The checkboxes we have are:
Edges have a very slight impact on how edges are drawn. The Faces checkbox decides if a selected face will be highlighted when selected or not while center will show a dot in the center of every face.
I would highly encourage you to always keep center checked since it gives a very good indication if we have faces hidden where they shouldn't be.
For instance if we accidentally extruded and then right-clicked to abort the operation. The geometry will still be created but it will be hidden in exactly the same place as the original mesh, making it almost impossible to see. This setting will help us spot any such accidents faster.
If you find these kinds of errors they will have a dot in the middle of an edge. To clean this up you can select the troublesome area, press M and merge by distance.
Just below we have four buttons that we can toggle on or of, just like checkboxes really.
These are all different kinds of edge marking we can use. You can see them when an edge has a specific color. Each button just toggle the marking color in the viewport.
This section is only have one setting and is only available if we enable it in the developers extra features in the user preferences. First go to Edit→Prefernces and find the interface tab and check Developers extras.
While in edit mode we get an indices' checkbox. This will display the id number associated with each vertex, face or edge that we select. This can be helpful in certain situations. For instance if we are developing and add-on that need access to this data or if we are using an add-on like Sorcar to create mesh with a node setup.
In this category we start with hidden wire. This is a bit unintuitive in my opinion because it actually hides the mesh and shows only the wireframe.
Vertex group weights are available here as well as in vertex paint mode. When enabled it displays more settings. In edit mode it only displays zero weights with three options:
With zero weight set to none we have our default weight display from blue through green and yellow to red for fully weight painted. With this set to active, zero weight vertices will be black for the current group to easier identify low value painted vertices.
With this set to all, only vertices with zero weight in all vertex groups on this object will be black.
In weight paint mode we also have an opacity setting that we can adjust to see the underlying shading through the weight paint colors.
Mesh analysis is related to 3D printing and help identify potential problem areas. When enabled we get to choose the type of mesh analysis we want to see.
These are different parameters we can check against with mesh analysis. Depending on the type and settings for each given type, we will see warning colors from blue to green, yellow and red for the parts that most closely match the analysis. Red being a full hit while blue has no hit at all.
It does not mean that our geometry is bad. It just means that for whatever settings we chose to display, parts for our mesh matched the parameters more or less depending on the color and if we intend to print we may need to sort these areas out.
Mesh analysis is very well explained in the Blender manual here:
External content: Blender manual, Mesh Analysis
We will just touch on each briefly here:
Overhang highlights any mesh that is angled towards a specified angle. Most likely the Z axis to see how much potential overhang we have and where support material may be needed for 3D printing.
Thickness highlights the thickness based on set values. This is because some 3D printers may have trouble with too thin geometry.
Intersect shows areas that the printer may have problem to decide if it is the inside or outside an object. This analysis type has no parameters, it is simply on or off.
Distortion is showing faces that are quads or n-gons and the angle of the face is such that triangulation can't be determined properly. The 3D printer may choose to triangulate these faces in some other way than Blender.
Sharp shows edges that may be too sharp to print. At the very edge the sharpness may make the geometry too thin.
This section is useful for those that model according to scale or even if you just want an approximate size for your object. For instance, if you are selling 3D models, doing some CAD design in Blender or use it for 3D printing.
We have four different measurements we can display.
Edge length will simply show the length of a selected edge in the unit you have specified. By default, the metric system is used.
You can read more about accurate measuring in this article:
Related content: How to accurately measure in Blender
Edge angle will display the angle between two selected edges. By default, this will be in degrees but radiance is also available. You can change the units in the scene tab in your properties panel.
Face angle will show the angle of each corner when a face is selected. It tends to get very cluttered and you will probably only use it occasionally if edge angle is not enough.
We also have face area. This will display the square meter size of each selected face.
I have found the normals settings to be useful primarily for two reasons. To troubleshoot bakes and check the normal directions.
We can check any of the vertex, edge or face icons to turn on visibility for each type of normal. This way we can see if normals are averaged or split.
We can also see if they point in the right direction. Helping us troubleshoot shading issues.
For example if we have flat shading on, each vertex normal will have one normal showing for each connected face. In opposition, we will see only one vertex averaged between the connected faces when we use smooth shading.
If the normals are hard to see we can also adjust their length with the size slider.
This can greatly help us see if bakes between high and low poly meshes will work as expected. Set the normal size to the same value as the ray distance or extrusion in newer versions(2.90) of Blender. This way we can get an accurate visible representation of how far rays will be cast as well bake.
If a ray misses we can adjust the extrusion value accordingly.
Here we have two settings. Edge mark and face marks. They simply show or hide the respective markings for freestyle. If you want to learn more about how to render freestyle, you can read my extensive guide on it here:
Related content: A guide to Blender freestyle rendering with Eevee and Cycles
So far we covered most overlay settings and their use cases, but we got some cases that didn't fit into edit or object mode.
In sculpt mode we have two additional settings except the object mode overlays. Mask and face set these both have a toggle and an opacity slider.
In texture painting we can set the stencil opacity.
At last, we have edit mode for curve objects. Here we can choose if we want to display the handles on our curves control points or just the control points themselves.
We can also choose to display the direction of the curve.
That is probably plenty more than you ever need to know about overlays in the viewport in Blender. This has been more of a rundown than an actual guide on how to do something. But all these overlays have their place and if you have heard of them it is much easier on the rare occasion you need one of them that you use seldom. But it may save you a lot of time to know that some of these are avaialble.
Thanks for your time.