Glossary of terminology

alignment

If an image is loaded into 3DSOM Pro that doesn't include the calibration mat then 3DSOM Pro cannot use it until the camera location has been defined. This process is called "alignment" and can also be used to adjust the camera position for other images that do include the mat.

backdrop

A plain coloured sheet of card placed behind the object in each photograph to help 3DSOM Pro to automatically separate the object from its background.

calibration mat

The calibration mat is a simple pattern of dots that needs to be placed under the obejct to be modelled when it is photographed. This allows 3DSOM Pro to automatically work out the exact positioning of the camera relative to the object in each photograph.

clipping

Clipping is used to remove unwanted geometry from the stand under the base of the model. A horizontal 'clip plane' can be moved up and down to choose the cut-off point and then all geometry below that is removed leaving the model with a flat bottom surface.

decimation

The number of triangles in a triangle mesh can be reduced continuously by a technique known as "decimation". At each stage, a single vertex is removed from the mesh and the surface re-triangulated around the missing vertex to produce a closed mesh with one fewer triangles. Which vertex to remove is carefully chosen to minimise the impact on the shape of the surface.

mask

Each image in the project can have an associated mask that defines where the object lies in the image. 3DSOM Pro uses this boundary between the masked and unmasked regions of an image to define the outline of the object in that image. The outlines in all the images in the project are used to define the shape of the object in 3D.

model

The virtual representation of your object in the computer as opposed to the real physical object you started with.

point cloud

3DSOM Pro version 3 can calculate a cloud of points by matching the object surface texture (or pattern) in pairs of photographs (if you have multiple cameras and a digital projector you can project a pattern onto plain object surfaces). Each point represents a 3D position in space and is displayed with a colour depending on which pair of images was used. You can also manually define straight edges, curves or marker points in two or more images to create additional sampled 3D points. The point cloud can be used when optimising the surface to create more accurate surfaces with concavities.

rejected

Images can be marked as "rejected" which means that they will not be used for subsequent operations such as creating the geometry or textures.

stand

A stand is highly recommended to raise the object up above the calibration mat when taking photographs so that most of the object appears against the backdrop.

subdivision surface

As well as storing the surface as a triangle mesh, 3DSOM Pro can compress this vastly by approximating it with a subdivision surface". A subdivision surface is stored as a "base mesh" which is just a simple triangle mesh but with very few triangles. A final mesh for rendering can then be created from this using subdivision to produce a smooth and detailed surface.

synthetic view

A view created from the virtual model rather than by taking a photograph - useful for editing the shape of the geometry from angles which were not originally photographed or were inaccessible.

texture map

A texture map is simply a colour image that is wrapped around the model surface to reproduce how the original object looks.

triangle mesh

3DSOM Pro creates a 3D model as a continuous surface (possibly in several disconnected pieces) made up of triangles, called a "triangle mesh".

view-dependent texture

The normal texture map looks the same from all directions, but in reality, the surfaces of objects can vary as you view them from different directions. The view-dependent texture map attempts to capture some of this variation by using different texture maps from different directions and blending them together as you move around. The cost is that it takes up much more memory and disk space to store the additional information.

wireframe model

The 3D model that 3DSOM Pro creates before the texture is applied is often referred to as a "wireframe" model.