Oblique Photography（osgb/3dtiles）
Oblique photography is a remote sensing technology that uses images collected by drone-mounted cameras and other equipment to photograph the target area from different angles (usually multiple oblique angles), and then generates a real-life three-dimensional model, thereby reflecting the real world over a large range, with high precision and high definition.
1. Model format conversion (osgb to 3dtiles)
Usually, oblique photography models are in osgb format, which cannot be directly connected to Wings Engine. We need to convert it to 3dtiles format first. This can be done using third-party tools.
2. Import the oblique photography model
First, click “+ New” in “Project” and select “GIS Blank” to create a blank GIS scene.
Click “GIS” in the toolbar, select “3DTiles”, and click “+” to import oblique photography.
Paste the JSON address of the oblique photography into the box and click “Import”.
Before successfully importing the oblique photography, the following prompt box will pop up, just click “Confirm”. Creating a new origin based on the center point of the oblique photography is convenient for subsequent configuration of the oblique photography.
In this way, we have successfully imported the oblique photography model.
We can adjust this so it lines up with the terrain.
3. Settings for oblique photography
Click on the oblique photography layer on the left to make relevant settings.
(1) Monolithization
Monolithization refers to the process of isolating models from oblique photography so that they can be interacted with independently.
(2) Free view
Free view is a view with higher degree of freedom, which allows you to observe objects or scenes from any angle. In this view, you can freely rotate, pan and zoom the view to better view various parts of the object.
(3) Top view
The top view is a view of an object or scene from above. In this view, the top of the object is visible, while the bottom is hidden. This view is often used to show the overall shape and structure of an object because it can clearly show the relationship between the various parts of the object.
3.1 Basic Settings
| Configuration items | Description |
|---|---|
| Visible | Determines whether the model is visible or hidden in Wings Engine. |
| Enable Hover | It needs to be used in conjunction with the “Monolithization” function. By enabling this button, the movement of the mouse within the image will be captured and responded to. |
| Latitude and longitude offset | The image coordinates can be moved to a suitable location. The default longitude and latitude coordinates are “0, 0”. |
| Height Offset | The offset image elevation data can be moved to a suitable position, and the default height position is “0”. |
| Opacity(%) | Commonly used in conjunction with conditional styling/interactions/multiple states to achieve model visibility and invisibility. |
| JSON File Address | The file address of oblique photography, you can change the file here. |
| Monomer Elimination Accuracy | This setting needs to be used in conjunction with the “Monolithization” option. The higher the precision, the smoother the edges of the monolithized part; the lower the precision, the rougher the edges. |
Click the “Color Condition Case” button in the “Basic Settings” of the oblique photography to set the color conditions separately.
Click the upper right corner of “Color Condition Case” to add, copy and delete color conditions. You can add multiple configuration items here.
Tip: “Color Condition Case” in oblique photography is generally used to set the image to display different colors when it meets different conditions. This setting item requires grammatical operations, which is difficult and is not recommended.
3.2 Light Settings
| Configuration items | Description |
|---|---|
| Exposure | The exposure determines the brightness of the image, and the default exposure value is “0.2”. The larger the value, the brighter the oblique photography part; the smaller the value, the darker the oblique photography part. |
| Use Standalone Light | After turning on this button, the ambient light intensity and sunlight intensity of the oblique photography part can be set separately. The default ambient light intensity and sunlight intensity values are both “0.1”. |
| Brightness | Brightness is used to describe the lightness or darkness of the image surface, and the default brightness value is “0”. The larger the value, the brighter the oblique photography part; the smaller the value, the darker the oblique photography part. |
| Contrast | Contrast refers to the measurement of the different brightness levels between the brightest white and the darkest black in the light and dark areas of the image. The default contrast value is “0”. The larger the value, the darker the oblique photography part; the smaller the value, the whiter the oblique photography part. |
| Hue | Hue can distinguish various colors. It is the texture of the color. It is composed of primary colors, intermediate colors and complex colors. The default hue value is “0”. |
| Lightness | Brightness is used to describe the brightness of the image. The default brightness value is “0”. The larger the value, the brighter the oblique photography part; the smaller the value, the darker the oblique photography part. |
| Saturation | Saturation refers to the brightness of the colors in an image, also known as the purity of the colors. The default brightness value is “0”. |
3.3 Load Policy
| Configuration items | Description |
|---|---|
| Skip Level of Detail | Turn on this button to skip some tiles and save memory. |
| Prefer Leaves | If this button is turned on, the detailed model will be loaded first. By default, the less detailed model will be loaded first. |
| Preload When Hidden | By turning this button on, images will be shown/hidden faster in your project. |
| Maximum Screen Space Error | The texture detail or granularity of the image surface, the default roughness is “16”. If the image roughness is high, the image surface may appear less smooth. |
| Cache Bytes | The default L1 cache size is 512MB. When the cache is insufficient, tilted images beyond the screen will be discarded and will need to be preloaded before entering the screen. |
| Maximum Cache Bytes | The default L2 cache size is 512MB. When the cache is insufficient, the image error will be automatically increased. |
4. Monolithization and Interaction
In general, oblique photogrammetry is not constructed by building but is segmented into parts. Therefore, typical oblique photogrammetry cannot meet the requirement of interacting with individual buildings. To address this, Wings Engine offers a visual interface for performing monolithization of oblique photogrammetry.
Click the “Separate” button in the upper left corner of the image interface to enter the monolithization settings.
Use the mouse to click, connect the points with lines and then form surfaces, and select the building you want to separate.
You can see that a “Unit Build” appears under the oblique photography layer.
Click to select “Unit Build0” to set the area.
| Configuration items | Description |
|---|---|
| Overlay Color | Individually configure the color for the overlay layer of the monolithized area. |
| Is Clipping | Enable this button to remove the monolithized area, achieving a hidden effect in the image. |
| Is Flatten | Enable this button to flatten the monolithized area to ground level. |
| Height Offset | Move the elevation data of the offset image to an appropriate position, with the default height set to “0”. |
After isolating a specific building, it can be used for interactive operations with other widgets in the project.
Switch to the GUI and add a “Pop-ups” widget.
After adding, switch to the 3D scene again. Select “Unit Biuld0” and add interaction for it in the “Interaction” settings menu. The specific settings are as follows:
Clicking Unit Build0 in the oblique photography will interact with the pop-up component in the dashboard, and the effect is as follows:
