• Price: 840 . 315

  • Company: Realviz

  • Pros: Allows you to reconstruct virtually any object from a series of images and export them, fully-textured, for use in 3D projects.

  • Cons: Marker placement and setup can be extremely boring and increases with the complexity of your project, and the program is pricey, too.

  • Our Rating: We rate this 8 out of 10 We rate this 8 out of 10

Image-based modelling as a technique is becoming commonplace in certain sectors of the 3D market, such as in film and broadcast production and pre-visualization. It’s not as common a practice to use such technologies for general-purpose modelling though, partly because you need to have reference photos of the object you want to model, and partly because it requires less skill than modelling ‘freestyle’. If you’ve spent years learning to model in 3D it’s likely you’ll want to make use of those skills, and reap the kudos resulting from a job well done.

However, there are certain circumstances where accuracy, speed, and other factors mean that modelling a given object by hand is too difficult or impractical. This is where programs such as ImageModeler become extremely useful.

ImageModeler by RealViz uses a process where 3D data is extracted from a series of photographs using technology similar to that used in the company’s matchmoving software. By placing markers on corresponding locations in different images (taken from different angles) ImageModeler can calculate the relative positions of the points in 3D space, taking into account the camera’s focal length and other factors. For the process to work you need a minimum of two photos of the scene or object, taken from different viewpoints. The further apart the viewing angles are the more chance ImageModeler has of calculating the positions of markers accurately. To help the calibration process (where ImageModeler calculates relative positions of markers) it’s beneficial to have points in the surrounding scene which can be marked as well. It may be necessary to add reference objects for this purpose if none exist that are suitable.

Repeat after me

The process and workflow are quite simple. You load all the images you want to use for your project (minimum of two) and begin locating and placing points. Choose a well-defined point in one image and place a marker there. As you click the mouse, a box opens displaying the magnified portion of the image to aid placement of the marker. Then, you switch to the next image, select the marker you created previously from a list in the interface, and locate the same point in the new image. The marker cursor turns white to indicate you are locating an existing marker in a new image as opposed to creating a new one.

This process is repeated for a minimum of seven points, though the more you add the better it will turn out – RealViz recommends between seven and 20. If you have several images this process can take quite a while, and the repetitive process is deathly dull and feels like the 3D equivalent of working on a factory production line. This is the single most annoying aspect of ImageModeler, and image-based modelling applications in general – they are utterly boring to use. However, once markers are placed and the scene is calibrated, things start to get more interesting.

Recreating 3D objects is ImageModeler’s purpose, and version 4 offers various tools for object regeneration. The simplest way to model is by adding primitives and editing them to suit the object. For buildings and other regular objects, this is quite simple. ImageModeler offers a number of finer tools that help with reconstructing forms that are more organic. Once modelling is complete, textures can be extracted from the reference photos and the final, fully textured object exported in various 3D formats.

ImageModeler 4 has been improved by offering two new calibration constraints, Survey Points and Planar constraints. The new Integration tool helps when importing existing 3D models into ImageModeler scenes allowing them to be more easily aligned and oriented with markers. The user can now control texture mapping, which is handy when the automatic texturing is occasionally less than ideal. You can also texture map objects using image files you have on disc – as you would in a regular 3D program. This is a great feature, because you can take photos (and edit them in Photoshop) specifically for texturing, rather than using the reference images. UV editing is offered too, making the placement of images much more accurate, though the interface could be a little more refined – we couldn’t find options to actually move UV points independently.

Other features include QuickTime VR Object rendering, a new distance snapping feature, and viewport ‘rendering’, which lets you dump the view contents as a JPEG file.

Overall, ImageModeler is a useful tool for projects that can’t realistically be completed another way. The upgrade, while not earth-shattering, is worthwhile. It would be great if some kind of automation could be developed for the more mundane parts of the workflow.

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