Classic picture

Select the image "TextureRefPoint.jpg" and go to Estimate Pose. The view will be automatically divided into two parts:

• On the left, the texture to map;

• On the right, the mesh to texture.

Click now on a point on the mesh and then the corresponding point on the picture (or vice versa). You can click angles or details in order to be more accurate. All the couples should be sufficiently distant in order to map correctly the texture. Click the Remove button in order to remove a pair of point. Once you have entered four couples of points, you can see the position of the camera in the 3D scene by clicking on Preview.

If you have some difficulties to enter the points, you can empty your list of points and then press the Load button and select the file "TextureRefPoint.txt". You will have a sample with 7 couples of points. Note that in most of cases, 4-5 couples are sufficient. But if you have a distorted picture (for example taken with a “fish-eye” lens), you will have to enter more points (probably 10 couples).

At any time, when you think that your reference point definition is correct, click the OK button to validate.

Then select the mesh and the image "TextureRefPoint" in order to launch Texture from Images.

In addition to the camera position, the software needs to know which triangles have to be textured according to its visibility from the point of view. The problem is that the definition of “visible” is not always clear because:

• Some triangles can be partially hidden by other surfaces.

• Sometimes the model is not correctly measured and you get some hidden triangles because of noisy parts.

In this example, select the option Fully visible triangles and then click Preview. If you turn the 3D view a little bit, you will see some non-textured triangles because at least one of the three vertices is not visible from the camera point of view. Then select the option Invisible parts and click Preview again. All triangles will be textured.

On the left, only visible triangles are textured; on the right all triangles are textured, but it creates blurring zones.

Once the result of your preview is correct, you can validate with the OK button.

Picture with distortion

If you want to practice more, you can redo the exercise with the picture “TextureRefPoint-Distortion.jpg”. You will have to enter more couples of points in order to compute the lens distortion. You will have to click points all over the picture, including on the corners. You can import the file “TextureRefPoint-Distortion.txt” in order to have a sample.