The Complete COLLADA to DGN Conversion Guide

Multiple UV Channels Support:

COLLADA: Full support | DGN: Partial support

DGN Notes:

Limited multi-texturing capabilities

Impact:

Multiple UV channels allow the optimized and sophisticated use of various 3D modeling features at once. For example, one can use one set of UVs and 2D texture data to model a tiling texture or procedural material, and another UV set to leverage a global lightmap or occlusion map of the 3D model. In this example, a combination of tiled texture (UV channel 1) and baked ambient occlusion map (UV channel 2) is used. Without support for this feature, one needs to either give up the tiling property (e.g., by using a tool like RapidPipline to bake a single texture atlas), or give up the ambient occlusion map, as only one UV channel will be usable.

Procedural Textures Support:

COLLADA: Partial support | DGN: No support

COLLADA Notes:

Basic procedural material definitions

Impact:

Procedural texture allow the modeling of surface details through mathematical functions, along with artistic control over various parameters. Typically, they are used for patterns like wood grain or other semi-regular structures. Since they are not using any pixels as source data, procedural textures have, in principle, infinite resolution and are very lightweight to describe. In this example, a procedural texture is used to model the look of a wooden material. Without support for this feature, in this case, the wooden parts won't show any visible details.

Normal Mapping Support:

COLLADA: Full support | DGN: Partial support

DGN Notes:

Basic normal mapping for visualization

Impact:

Normal maps are used to model shading differences that are arising from small geometric details on a surface, such as fabric structures, visible gaps between bricks forming a wall, or rough rock surfaces. In this example, a normal map is used to model a fabric structure. Without support for this feature, the rendered fabric will look smoother than it actually is in the real world, as the fabric structure won't be visible.

Animations Support:

COLLADA: Full support | DGN: Partial support

DGN Notes:

Simple animation support for design sequences

Impact:

Animations are an important part of many interactive 3D assets, for example in real-time rendering (including games, XR training, assembly instructions, product demos, and other use cases). There are various kinds of animations that can be used on 3D models. In this example model, a rigid animation is used to make the gears spin. Without support for this feature, in this example, the gears won't move.

Skinned Animations Support:

COLLADA: Full support | DGN: No support

Impact:

Skinned animations are commonly used for 3D character models in interactive applications, such as games or virtual worlds. They make it possible to easily animate the 3D model using a helper structure based on virtual bones, composing a virtual skeleton for animation control. In this example, a skinned animation is used to pose a 3D character. Without support for skinned animations, the 3D model will remain in its default pose, such as the default T-pose.

Morph Targets Support:

COLLADA: Full support | DGN: No support

Impact:

Morph Targets, or "Blend Shapes", are commonly used to animate facial expressions and soft surfaces, for example cloth under a cloth simulation. They model various states of the animations with different vertex positions. In contrast to skinned animations, morph targets do not use any virtual bones, but work solely on the vertex data. In this example, a facial animation is achieved through morph targets. Without suport for this feature, in this example, the face will not show the animation.

Rigid Animations Support:

COLLADA: Full support | DGN: Partial support

DGN Notes:

Basic animation for construction sequencing

Impact:

Rigid Animations are typically used to animate mechanical parts. In this example, the door of this 3D model of a microwave can be interactively opened or closed, using a rigid animation that gradually changes the 3D transformation of the door. Without support for this feature, in this example, the door will just stay in place and won't move.

Standardized Format Support:

COLLADA: Full support | DGN: Partial support

DGN Notes:

Open specification with some proprietary extensions

Impact:

Standardization plays a huge role in 3D model formats. With a format being standardized, every application will have a clear way of how to load or store data using this format. This makes it easier to re-use the 3D model across different applications, but also to make sure it will still be accessible and usable after a couple of years.