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Emergency Light

A step-by-step beginner tutorial designed to learn the basics of creating UV coordinates using the Zen UV addon. In this tutorial, you will learn the basic rules of creating UV unwraps and how to use the Zen UV tools for quick and comfortable work. You will receive basic information about the rules and recommendations for creating UV coordinates for game engines.

The tutorial covers the main stages that are optimal steps for processing any model:

• Model preparation
• Initial unwrap
• Analyze the initial unwrap
• Step-by-step unwrapping of parts
• Packing
• Optimization

Prepare scene

Download example

1. Check that internet connection is enabled in Blender (this option is available since Blender 4.2).

   • Click on “Internet Connection” icon.
   • Enable internet access.

   

2. Using the examples panel, select and download the example called “Emergency Light Tutorial” by clicking on the “Download” button to the right of the title.

   

3. When the scene is downloaded, click the “Open” button that appears in place of the “Download” button.

   

4. Select “Emergency Light” object and switch to Edit Mesh mode.

   

Prepare model

1. Zen UV uses global mark system by default. Let’s change mark settings to mark Seam and Sharp at the same time.

   • Select Unwrap tab and find “Properties” button placed to the right of “Mark by Angle” button.
   • Press it and in popup menu enable “Mark Sharp Edges” option.

   

2. Press Unmark all button in Unwrap tab to clear all existing Seams and Sharp edges.

   

3. Let’s check than there are no islands marked as Finished. Finished tags helps to visually control islands state (finished/not finished) and prevents Zen Unwrap operator to re-unwrap Finished islands.

   • Select all polygons.
   • Expand Finished panel in Unwrap tab and press Tag Unfinished.

   

4. Delete all UV Maps.

   • Switch to Advanced UV Maps tab.
   • Select all UV Maps.
   • Press “-” (delete) button.

   

   Tip

   Zen UV automatically control UV Maps and will create new one if there are no, so there is no necesserity to create UV Map manually.

5. An important part of the prepare is to check the scale of the objects for which UV coordinates will be created. The scale of each object should be equal to (1.00, 1.00, 1.00), as it can affect the work of the unwrap operators. Also, an incorrect scale can affect the relative size of islands when packing and when setting textel density. Editing the scale of objects is performed in Object Mode.

   • Turn on Object Mode.
   • In the 3D View main menu, click Object - Apply - Apply Object Transform.
   • Make sure that the object scale is (1.00, 1.00, 1.00).

   

   Tip

   Scaling and other object transformations are used primarily for animation and other purposes. If you’re working with objects that have animations or form a hierarchy, performing Object - Apply - Apply Object Transform is dangerous because it will distort the animation and destroy the hierarchy.

Initial unwrap

1. Now when everything is ready, we can start unwrapping. The first step is to split the model into UV islands. At this stage, it doesn’t matter how well these islands are unwrapped. We just separate them. We will mark the seams depending on the edge angle. Sharper edges will be marked as seams and thus define the places where the model will be split.

   • Turn on Edit Mode
   • Press “Mark By Angle” in Unwrap tab.

   

2. Almost all Zen UV operations could be executed in 3D View, but it is more comfortable to visually control them in UV Editor. There is a special UV Editor gizmo widget in 3D View.

   • Press Open UV Editor button placed at the left center part of 3D View viewport. The button works as toggle, so if UV Editor is open it will be closed.

   

3. We have created seams depending on the edge angle, but have not yet divided the model into islands. To do this, we will use the Zen Unwrap operator, which works depending on what is selected. So at this stage, make sure that nothing is selected. In the mode when nothing is selected, Zen Unwrap simply splits the model into UV islands along the existing seams. If something is selected, the result will be different.

   • Deselect all.
   • Press Zen Unwrap button from Unwrap tab.

   

Other modes of Zen Unwrap operator will be demonstrated later in this tutorial.

Switch on checker texture

1. At this stage, we have a basic division of the model into islands, but this is not enough. We need to visually check the model, create additional islands, and in the process straighten the existing islands if necessary. At this stage, it is important to improve the perception of artifacts in order to complete the work as quickly as possible. One of the most effective methods is to assign a special texture consisting of squares.If you see on the model that the squares are distorted or have a shape that is far from square, this means that the mapping in this place is incorrect. We are applying the special checking texture using Zen UV Checker module.

   • Press “Checker Texture” button in UV Checker tab.

   

2. Colored textures are also created to determine the location of the island on the texture. But in our case, it doesn’t matter. So let’s switch the texture to monochrome. This will reduce the amount of information to be perceived and therefore reduce tiredness from work.

   • Open drop-down menu below “Checker Texture” button and select texture zen-mono-2048x2048.

   

3. The next step is not important for this model, but you may need it in the future. Let’s disable the display of all types of edges except seam. These properties duplicate the native display system options, but now they are in close access in the UV Checker panel. Remember about the tiredness of information overload.

   • Disable “Crease”, “Sharp”, “Bevel” in Blender draw system panel. Check that only “Seams” are left.

   

4. Textures for checking usually have a rather aggressive look and interfere with the perception of islands in UV Editor. Zen UV has the ability to darken the current texture for comfortable perception.

   • Use the Darken Image operator located in the UV Checker panel of the main addon panel in UV Editor.

   

   Tip

   Darken Image could be also found in UV Editor overlay properties.

5. Also we can simply delete texture in UV Editor because in this tutorial we will not use it for analysis in this context.

   • Find active image property in the top of UV Editor and delete it.

   

Unwrap

Preparation is completed. Let’s continue with model unwrapping. It is convenient to divide this process into steps. Our model consists of several parts. So let’s conditionally divide it into stages corresponding to each part separately.

Unwrap internal cylindrical part

1. Let’s start from cylindrical part.

   • Select it in “UV Editor”.
   • Press Isolate Island button in Select tab.

   Tip

   This operator works like a toggle. This means that if you press it again now, everything that is hidden will appear again. It works in the same way as for 3D View and UV Editor.

   

   The main operator for creating islands in the Zen UV addon is Zen Unwrap. This is a multifunctional context operator. It performs different tasks depending on the following:

   • Which selection mode is currently active.
   • What exactly is selected at the time of its start.
   • What additional properties are enabled.

   Zen Unwrap tracks three main selection modes.

   • Faces
   • Edges
   • Verices

   If Blender is in Faces selection mode, a new island will be created from the selected polygons, and the edges along the border of the selected polygons will be marked as seams. Let’s use this to create the first island.

   • Select cap and press Zen Unwrap in Unwrap tab

   

   Several more islands will be created in the process. They may be incorrect or not the same as in the video, but it doesn’t matter now.

2. Let’s use the Edges selection mode to unwrap the next island.

   • Switch Blender to Edges selection mode. In this mode, Zen Unwrap will create seams for the selected edges and perform the unwrap.
   • Select one edge on the longest cylinder and click Zen Unwrap.

   Tip

   The places where seams will be created can usually be too visible on the texture and will require additional masking. In order not to waste time on this, try to create gaps in places that are not very visible. So, in our case, it is recommended to select one of the lower edges because it will definitely be covered by the outer part of the model.

   

   As you can see, Zen Unwrap follows your instructions exactly and unwraps the islands despite the fact that we change the selection type. You don’t even need to open its settings to do this. As a result, we got the largest island of this part correctly unwrapped.

3. Unwrap the second cap.

   • Switch Blender selection into Faces mode.
   • Select cap.
   • Press Zen Unwrap.

   

4. When using Mark by Angle, unwanted seams were created, which divided the model into more islands than necessary. To fix this, use the Zen Unwrap operator again.

   • Select all the polygons of the largest cylinder and press Zen Unwrap. As a result, all the selected islands are merged into one, and the edge of the selected polygons are marked as seams.

   

5. At this point, we’ve finished creating the islands, but many of the islands are still deformed. You can switch to edges selection mode and follow the same steps as for the largest cylinder, but the islands that have a slightly more complex shape will not be aligned sufficiently. Let’s use the Quadrify operator, which aligns the islands created from quads into a square grid.

   • Switch to edges selection mode.
   • Select one lengthwise edge, and click the Quadrify button in the Transform panel.

   

   Tip

   Such usage of the Quadrify operator is fast but not always optimal. If you do not specify to the operator where you want to make a break, the island break will be created automatically and may not be in the optimal location. For full control over the creation of the gap, use the Use Selected Edges option. You can also create a gap before using Quadrify using other methods.

6. Let’s change some operator properties.

   • Open the operator properties panel.
   • Activate the Use Selected Edges option. This will tell the operator to split the island along the selected edge.

   

   • Do the same for all remaining islands.

   

7. Now some islands in the UV Editor may overlap others. In order to make sure that each island is unwrapped correctly, we will perform a packing. This will improve the visual perception of all the islands.

   • Click the Pack Islands button from the Pack panel.

   

8. We will continue working on other details soon, but first we will use the Finished system. This will make it possible to visually control which islands have already been unwrapped and protect finished islands from being unwrapped again.

   • Go to the Unwrap tab.
   • Expand the panel called Finished.
   • Select all the islands.
   • Click the Tag Finished button from the Finished panel.

   

Unwrap external part

1. Go to the next detail. To do this, we need to unhide all the parts of the model.

   • Click Isolate Island from the Select panel to unhide all hidden islands.

   

   • Select the part of the model that looks like the outer shell.

   

   • Click Isolate Island again. Now we have only the part we need visible. The other parts are hidden and will not get in the way.

   

2. This part has clear contours, correct seams, but some islands could be improved. The inner part is a cylinder that can be represented by one island instead of several. Let’s create one island from the interior.

   • Select the entire interior except for the island, which is a polygon.
   • Click Zen Unwrap.

   

3. The created island may look better if you align it into a square grid. Use the Quadrify operator. Please note. If you have the Use Selected Edges option activated, then you’d better switch to the faces selection mode. Because in the edges selection mode, the Quadrify operator will break the island along the selected edges. Also, note that Zen UV is always trying to help you, and in order to tell the operator which island you want to work with, you do not need to select the entire island. It is enough to select one or more polygons.

   • Select one or more polygons in the island inside the current part, and then click Quadrify.

   

4. The next island is too large, cyclic, and inverted. To get rid of these problems, divide it into several smaller islands.

   • Select the side edges.
   • Click Zen Unwrap.

   

5. The island representing the upper end is correctly unwrapped, but we can make it more compact. Also, we need to make sure that the boundary edges of any island are aligned along the axes as much as possible. This will make gaps in the texture much less obvious.

   • Select one or more faces of the top island.
   • Click Select Island from the Select panel.
   • Switch to the top view and use the Project From View operator to create a flat island from the selected polygons.

   

6. Splitting into islands is done. Make Pack and Tag Finished in the same way as previous parts.

   

7. Click Isolate Island to show all other parts and be ready for the next step of the tutorial.

Unwrap small details

1. Isolate small details for more comfortable work.

   • Select all small details.
   • Click Isolate Island

   

2. The Mark by Ange operator worked correctly on all small parts except for cylindrical parts. Let’s fix it.

   • Select one edge on each of the cylinders and click Zen Unwrap.

   

3. Go to the part that holds the wires together. It has been divided into several parts, which is not the optimal shape. It is enough to separate the ends and leave the rest as one island.

   • Select the entire part.
   • Deselect the ends.
   • Run Zen Unwrap.

   

4. We have created one island, but its mapping is still incorrect (Rectangles are distorted on Checker texture). We need to break and flatten the radial island.

   • Select the pair of edges where you want to split.
   • Run Zen Unwrap.

   

5. At this stage, we have the correct split into islands, but some islands have stretches. Some other islands are not optimally shaped. We need to select and align all the islands that consist of quads.

   • Use the Select Quaded Islands operator from the Select panel.

   

   • Use the Quadrify operator to align all the selected islands into a square grid.

   

6. Make Pack and Tag Finished to finalize unwrapping small details.

   

7. Click Isolate Island to show all other parts and be ready for the next step of the tutorial.

Unwrap wires

1. Isolate the wires for more comfortable work.

   • Select all the wires.
   • Click Isolate Island to hide all unnecessary parts.

   

2. You can see that each wire is currently divided into several islands. Let’s make sure that each wire is represented by a single island. Select all the polygons and click Zen Unwrap.

   

3. We have a split where each wire represents one island, but the unwrapping is incorrect. Let’s unwrap the wires in the fastest way.

   • Make sure that all islands are selected.
   • Use the Quadrify operator to align each island into an even grid.

   

   Tip

   In the case of unwrapping wires or other similar models, it is very convenient to use the Use Selected Edges option of the Quadrify operator, which we have reviewed earlier. This way we will get the breaks exactly where we need them on the first try.

4. Finally, we will pack for better visual control and mark the islands as finished.

   • Run Pack.
   • Execute Tag Finished to complete the wire unwrap.

   

5. Click Isolate Island to show all other parts and be ready for the next step of the tutorial.

Unwrap handle

1. Isolate handle for more comfortable work. Let’s use something from the Finished system.

   • Click Isolate Island to display all the parts.
   • Click Select in the Finished panel.
   • Click Hide in the Finished panel.

   

2. This part consists of several islands, which is not an optimal solution. Let’s create a single island instead of multiple islands.

   • Select all the islands that belong to the handle.
   • Deselect the ends that look like hexagons.
   • Click Zen Unwrap.

   

3. The island that was created as a result of the latter actions has an incorrect shape. Let’s fix it.

   • Select the edges belonging to the hole and the edges belonging to the inner edge of the handle.
   • Click Zen Unwrap

   

4. Now we have an unwrapped island. The presence of triangular faces in it does not allow to use the Quadrify operator for maximum smoothing. Let’s take this island as an example of how the Reshape Island operator works. The essence of Reshape Island is that it aligns the selected edge loops into a straight line and relaxes the remaining vertices.

   • Select all the edges that run lengthwise through the center of the island.
   • Click Reshape Island to align the island.

   

5. The island unwrapping can be considered complete. Let’s mark it as finished.

   • Run the Pack operator.
   • Select all the islands.
   • Tag them with Tag Finished to complete the unwrapping of the handle.

   

6. Click Isolate Island to show all other parts and be ready for the next step of the tutorial.

Pack

The previous stage of island creation and unwrapping is completed. Now it’s time to place the islands on the texture in such a way as to reduce the amount of free space. All free space on the texture is a waste of resources.

Final pack

1. Make sure there are no hidden parts. And then pack it up.

   • In the 3D View in the main menu, click Mesh - Show/Hide - Reveal Hidden.
   • Use the Pack operator to pack the islands.

   

Reduce empty UV space by stacking

1. At this stage, we have tightly packed parts and the work can be considered complete. But if you analyze the construction of the model, you will notice that some islands look similar and are even copies of each other. For example, the cutouts for bolts, the bolts themselves, some small details, etc. To save space on the texture, identical islands can be stacked on top of each other. In terms of creating UV coordinates, this process is called Stacking.

   • Open the Stack tab.
   • Click the Replicas button. Now we have selected islands that have copies. These islands are called Replicas. And their prototypes remain unselected.

   

   • Move the selected islands away from the UV Area. Now only unique islands that do not have copies (Singles) and islands that are prototypes (Primaries) remain in the UV Area.

   

2. In this tutorial, we are using the Blender Pack Engine. The following steps for packing will be described for this engine.

   • Hide the islands that have been moved to the side.

   

   • Set the correct (desired) Texture Size in the Pack panel. For this particular tutorial, the texture size does not matter, but you may plan to create a texture by another tutorial.

   

   • Set the required value to Margin, which will ensure the correct appearance of the texture when the camera is moved away.

   

   • Repack using the Pack button.

   

   • In the Stack panel, switch the system to Selected mode.
   • In order to show hidden Replicas in the 3D View in the main menu, click Mesh - Show/Hide - Reveal Hidden.
   • Select everything except Replicas.
   • Click Stack to stack the unselected Replicas in place of the selected Primaries.

   

The packing and stacking is completed. There are only a few final steps left to complete the model.

Set sharp edges

1. Correctly set sharp edges are not only a guarantee of a good appearance of the model, but also a guarantee of baking normal map without errors.

   • Use the Sharp by UV Borders operator. This operator marks the edges that are the boundary edges of the islands as sharp.

   

   • In the operator settings, turn on the Unmark sharp option. This will erase any sharp edges that have been previously set.

   

2. There are two ways to set the edge sharpness in Blender.

   • By setting the polygon property to Shade Smooth / Shade Sharp.
   • By using the Sharp edge property.

   Both methods can work simultaneously, which often leads to artifacts when using the normal map. Since we have already set the sharp edges as we need them using the Sharp edge property, let’s exclude the possibility of the Smooth/Sharp polygon property affecting the sharpness of the edges. In Zen UV, there is a Smooth by Sharp operator.

   • Click the Smooth by Sharp button. This will set all polygon smoothing to match sharp edges.

   

Now the Emergency light model has correct and optimized UV coordinates and is ready for texture creation and normal map baking.