A non-photo-realistic 3d visual of an exterior of a house. Created by using Piranesi software. looks at Non-Photorealistic Rendering

Sometimes the goal of a 3d visual isn’t about accurate photo-realism, but about giving a feel or flavour for a concept or design.

At we have always held a very soft spot for a lovely piece of software called Piranesi.

Essentially, Piranesi uses a special form of 3D image file allowing materials and finishes to be applied to surfaces to create a final non-photo-realistic looking image.

It does this very cleverly by using the all important z-depth information that is known for each pixel within the image (z-depth being the distance into an image away from the viewer’s eye-point).

In the gray-scale image below, it is clear that the pillars and railings in the foreground are closer to the viewer’s eye-point than the garage door and chimney stack further towards the back.  They will therefore have lower (smaller) z-depth values than objects that are further away from our viewpoint (for example the sky will have a z-depth of infinity).

A 3D Model of a house, ready for materials to be applied in 3D non-photorealistic rendering software, Piranesi

Furthermore, during the creation of such an image file (using 3d software such as 3ds Max), each particular object, or element will have been assigned an object name (eg. door, window frames, glass, grass, rooftiles etc) as well as a material name also.

What one can do with all this information within Piranesi is to assign Piranesi’s own real-world materials to each of these 3d objects and elements to give it that non-photorealistic look.

Furthermore, Piranesi is clever enough to wrap those materials intelligently around geometry, adding perspective as well all thanks to the z-depth information contained within.

Finally, Piranesi’s internal 3d model library allows for populating the scene with its own vegetation, plants, trees, cars and people as well as a adding a realistic background of trees, sky and clouds to add even more depth and realism.

Even the position of the sun to give shadows and depth is possible.

At this point of proceedings our image is complete in the sense that it does fulfil the role of being a non-photorealistic rendering.

Non-photorealistic 3D model with materials applied, ready for artistic effects

However, one can go one step further by applying different styles to our image to create any number of artistic effects and looks.

Here is a painterly effect on canvas as an example. - first non-photo-realistic rendering - with a painterly effect

In some instances – perhaps where we’re looking to simply convey a feel for a space or photo-realism isn’t first and foremost the largest requirement from our 3d visuals, non-photorealistic renders and imaging are well worth considering.