Uploading 3D Objects to Patches - Part 2

Blender

Import Files

Download the free 3D software Blender from https://www.blender.org/download/

After installing it, open it and you should see the default 3D view. Click on anywhere in the empty space to close the splash screen.

Blender default view

Before clicking on anything else, go to File > User Preferences

In this window go to the Input tab, and change the Select With option to Left. By default it’s set to Right click, which can be confusing when selecting objects. Click Save User Settings to save your changes.

Selection key option

If you are using a laptop or a keyboard without the Numpad, it’s recommended to check the Emulate Numpad option. This allows you to use the main 1 to 0 buttons similarly to Numpad keys.

Emulate Numpad

Now you can close the settings window and click on the default box in the 3D view. You can remove it with the Delete button on your keyboard. The same can be done to the camera, which is the black triangle. The small dot icon on the right is the default light.

Small dot icon on the right is the default light

After deleting the box and camera go to File > Import and select Wavefront (.obj) or another file format corresponding the file you downloaded from Sketchfab.

Import file

Search for the file location, click on it and press enter. Now the 3D object appears in the empty scene. If the object appears to be huge like in this example, zoom out with the Middle Mouse Button (MMB) scroll to see it better.

Imported file

To rotate the view click and drag with the MMB.
To pan the view press and hold Shift and drag the MMB.

Scale objects

If your file is large like this example, it’s good to scale it smaller. Select the object by clicking on it (the outline turns yellow), then press N to open the Transform properties window.

Transform options

Take a look at the Scale and Dimensions. If all Scale values are 1 it means the object is in it’s original size. The Dimensions might be in Blender units by default, so it’s good to change them to Metric system to match the measures in Patches.

To change units, go to the Scene options at the far right menu, the third icon on the row.

Scene units

Under the Units menu, select Meters from the drop down and change Length to Metric. Now the object measures show in meters.

To scale down the object, press S and drag your mouse to scale it down. Keep an eye on the Dimensions. To stop scaling, click anywhere on the screen to accept your new scale. For this example I scaled down the object until it was about 1 meter wide.

Scaled down object

Change Object Center Point

Often when downloading Sketchfab files the object doesn’t have a center pivot point. This means it will be difficult to scale and move the object in 3D space, because the pivot point is somewhere outside the model.

Example where the object is off the center point

To give the object a center point, move it by dragging the arrows until the area where you want the new pivot point to be is approximately at the center of the grid.

For easier object placement, press 5 on the Numpad (or main numbers if you have Emulate Numpad option on) to switch to Orthographic view. The numbers work as hotkeys for changing the view angle.

  • 1 = Front
  • 3 = Right
  • 5 = Othrographic / Perspective
  • 7 = Top
  • 9 = bottom
  • Other numbers rotate the angle manually.

Object moved in Ortho view

The orange dot is the object’s center pivot point. The goal is to move it to the center of the grid, where the red/white circle is located. This is the 3D Cursor which can be used to determine a new pivot point place.

To make sure the 3D Cursor is at the center of the grid, press Shift + C to reset it’s location.

At the far left menu on the screen is a drop down menu called Set Origin. If it’s not visible, make sure you are in the Tools tab at the top left corner of the menu. Click on it and select Origin to 3D Cursor. This changes the object’s pivot point to the 3D Cursor location.

Set Origin

New pivot point

Now the point has moved and is at the center of the object. This makes it easier to transform in any 3D scenes.

Decimate Objects

High resolution 3D models often have a lot of polygons, which is not ideal for the web. Blender has a simple tool for reducing the polycount while still keeping the geometry the same.

Select the 3D model (in this case the table) and in the far right menu go to the Modifiers tab, which has a wrench icon.

Modifiers tab

Click on the Add Modifier menu, and select the Decimate modifier.

Modifier menu

Now the object has the Decimate modifier.
The eye icon displays or hides the modifier in the viewport. When it’s dark grey it’s enabled and shows the modifier. The Ratio is the amount of reduction you want to do. 1 equals 100%, which means there is no reduction. 0.5 is 50% and halves the polycount of the object. Click on the Ratio type the value you want to try and press enter.

Default ratio Ratio reduced to 45%

For this example the ratio used is 0.45. Notice the difference in the amount of Faces under the Ratio. This shows how much geometry the object has after the reduction. Depending on how much the reduction is, you can see the change on the object in the view.

Without modifier With modifier

The most detailed part of this model changed to look slightly more simple. The best amount of Ratio is to have a value as low as possible but still keep the object almost identical to the original one. Making the value too low will start to break the object as it tries to find ways to reduce the polygons.

The modifier can be left on the list, or it can be applied to the object itself. Note that this will completely remove polygons from the object and won’t be undoable later on. To make the changes to the object, click on the Apply button on the Decimate modifier. The modifier then disappears from the list.

Export objects

The best file format to export for Patches is obj. To export your 3D object make sure your object is selected, go to File > Export and choose Wavefront (.obj).

File - Export - Wavefront (.obj)

This opens the browser window where you can name and choose where to export your file. The bottom left corner has Export OBJ options. From these options check the Selection Only and Material Groups options. Everything else is fine by default.

Export options

The export outputs two files: MTL and OBJ. The OBJ is the one needed for Patches.

Exported files