Purpose and workflow of wireframe models

Question

I am more less familiarized with the major computer graphics concepts up to certain dregree of "low-levelness". So I know how models, vertices, polygons etc. and how these works. Also how is the info in these (meaning the models) serialized and interpreted by a software, generally a game or graphics engine, to use this models info, vertices and indices, to get the model itself and handle it accordingly.

Thats why I was surprised when I found some wireframe models, because I am not familiar neither with the concept nor the purpose of these.

1.- Are these handled (seralized and de-serialized) same as regular vertices models? Back in the beginning of computer graphics guess this was about all a computer could easily do, but is there any other purpose?

2.- If there is a wireframe resource provided such as this, how it would me used/handled. In the case of a 2D isometric view game, I do not know what would I need to do with resources provided in this format. What would be roughly the approach? There are no vertices in this case, the wireframe is provided as a sprite resource, so what is it that needs to be done roughly to make use of it?

I am not after an specific algorithm to handle this, this is not a code question. I mean what would be the general concept/workflow for this type of resource.

Answer 1

1. Why are wireframes used?

   • Games don't really use wireframes much, but they might be useful for HUD items etc.

   • Asset creators, designers and engineers use wireframes to see whats inside objects. TO clarify the edged between elements or to preview unimportant aspects.

     

     Image 1: Different 3D views (click to zoom)

     Engineers and Architects also may have very complex pure line drawings, with millions of lines and they would like to have them accelerated. (Imagine having each brick in one layer for a shopping mall, along with lines for each strut, electrical wire bundle, each air and plumbing pipe and each furniture in one drawing.) Nothing kills productivity like having a sluggish CAD response.

   • Selection highlight etc.

     

     Image 2: Edge loop Selected and highlighted

   Note: Gamer card drivers don't frequently have, or have lacking wireframe acceleration routines, while the workstation versions of the cards do.

2. How are wireframes drawn?

   Same way as polygons, or just as lists of points to be joined

3. "If there is a wireframe resource provided such as this, how it would me used/handled. In the case of a 2D isometric view game, I do not know what would I need to do with resources provided in this format."

   its not a wireframe. Its a sprite sheet. Don't confuse the technical meaning of wireframe in computer graphics and how ui designers use the word to mean different things.

   Presumably your game engine has a method for defining sprite sheets. Otherwise you would just use a shader to make them.

   Its not really related to the body of the question you asked should be separated into a different question.

Answer 2

Regarding wireframes as an edge list.

Wireframe models are used in engineering and CAD they provide several benefits. The Wikipedia page you linked has some benefits, this AutoCAD page has some more. Wireframe are used less in games and movies since they are generally more concerned about the visuals and wireframes are more concerned about design (form over function). But wireframes can be converted for rasterization and will get used in games/movies but so far as I have seen are converted (to the appropriate format) first, ( I am going to guess that there are games that use wireframe almost exclusively, but I haven't had the pleasure...knock on wood)

The source you linked in the second question is not a edge list wire frame since there is no source for the edges provided. Sprites drawn as a wireframe are yet another thing again, usually the background is clear and the sprite is drawn over another sprite to give it an outline. Such as when it is selected or a mouse if hovering over it.

Games and most rendering tools overload the term "wireframe" when referring to a triangle mesh drawn as lines without filling the triangles, sometimes drawn as quads, again just as lines. This is not the same thing as a wire frame model either since a wireframe model is comprised edge lists.