Frequently Asked Questions


Q: Do you have a tutorial on how to use Polygonian?

Indeed. Check out this 2-minute video tutorial:


Q: Why is the app called Polygonian when only triangles are used?

Artworks created by Polygonian can be considered a subset of the “2D low-poly” genre, hence the name — though Polygonian uses only triangles, avoids pointy triangles by using strict Delaunay Triangulation, and colors triangles uniformly based on local averages.

Besides, I used to live in the Pacific Northwest and had a fond memory of being an Oregonian.


Q: What is triangulation? What is Delaunay triangulation?

Triangulation is the process of partitioning the image into a collection of non-overlapping triangles, typically by first adding a collection of vertices within the image, and then iteratively draw non-intersecting lines between vertices until all subregions are triangular.

Delaunay triangulation is a special kind of triangulation that maximizes the smallest angle within the triangles. As a result, you won't see awkward, sharp triangles, and the result is usually more pleasant. All triangulations created by Polygonian are Delaunay triangulations."


Q: Is Polygonian primarily about automation or editing?

It is both. I suggest you take full advantage of Polygonian by doing both.

First, Polygonian does it job very well as an automatic tool. You can just pick an image, and voila, the triangulation is done! You only need to decide if the source picture needs to be cropped, and what level of details you'd like to see.

Second, Polygonian provides a comprehensive support for manual editing. You can add, erase, and move vertices, and the triangulation is updated in real time; You can chose to simply specific regions of the triangulation; and undo/redo is fully supported.

Every one of the Polygonian artworks shown here is created either completely automatically in seconds, or followed by a small amount of edits measured in minutes."


Q: How does Polygonian decides how and where the triangles are created? The triangles seem random but not quite random?

Though the main goal is to create triangles that capture the essence of the source picture, Polygonian does not create the triangles directly, but rather makes decision on where (and how many) vertices should be added. The triangles are created through Delaunay Triangulation and their colors are determined to be the average colors of the pixels under the triangles.

Indeed, the placement of the vertices is hardly random. Polygonian performs careful analysis of the source image, taking into consideration the following factors: overall complexity of the source image, edges, color gradients, level of details provided by the user. Vertices (and hence triangles) are added judiciously, and only when deemed necessary to faithfully represent the picture or to highlight edges. Though far from perfect, Polygonian artworks compare favorably to many techniques that exist today."


Q: Is the Polygonian logo in the AppStore made with Polygonian? How?

Yes. Starting with what Polygonian gave me at medium detail, I stayed exclusively in “Move” pen mode to add, erase, and mostly move vertices around so as to showcase the best features of the face of Venus (from the painting Nascita di Venere by Botticelli), namely her eyes, lips, and eyebrows.

This artwork was created in approximately three minutes.


Q: I see an important line in the image but Polygonian did not capture it. What gives?

Polygonian may skip certain lines for various reasons: (a) in the grand scheme of things, it is a line but Polygonian considers it an unimportant one, (b) it is a line but Polygonian fails to detect it, (c) Polygonian acknowledges that this is a line, but there are too many lines to consider, (d) it is a line, but Polygonian doesn't know how to do it properly, perhaps because the line is too thick, too thin, or too crowded, (e) the image is too noisy!


Q: I want to edit the artwork so that a line exists where I want, how to do this?

You can add vertices along the line. Imagine you have two vertices that are meant to be connected together but no triangle edge connects them. You can add vertices between them, and thanks to the property of Delaunay Triangulation, sooner rather than later the intermediate vertices will be connected in order, hence forming the desirable edge you seek. How closely spaced the vertices should be depends on the actual configuration, but it is easy to get the hang of it through practice.

In the following example, Polygonian is missing an edge that completes the pelican beak. The problem can be fixed easily by adding a vertex in the middle of the missing edge.


Q: There are too many pen modes! They are confusing. Why don't you support just one?

You can always stay with the default, “Smart”, which is the most intuitive. You tap to add, tap to erase, and you can pan and zoom easily. This is the workhorse mode suitable for most users including young kids.

“Add” and “Erase” are the most useful if you know what you are doing, say, removing vertices in a certain region. Most will find them unnecessary.

“Move” is by far the most useful for professionals, because it contains all three useful actions in one — add, erase, and move. The move action is especially designed to allow very fine-grain adjustment without being obstructed by your finger. However, the prowess of “Move” comes with one disadvantage: you can no longer pan with one finger. This tends to confuse novice users, and hence “Move” is not the default pen mode. I (as a professional user) stay exclusively on “Move”, and always use two fingers to navigate.


Q: What is the reason for the warning — “Changing details will remove existing edits” — when I adjust the “Detail” slider?

Polygonian recomputes the triangulation from scratch when you adjust the slider. Previous edits, which include adding, erasing, and simplifying vertices and triangles, don't make sense any more when a new and different set of vertices is introduced. Also, automatic triangulation does not work as effectively if Polygonian needs to honor a half-obsolete constraint. I recommend you first find the most appropriate level of details — often the default 50% is more than sufficient — then make whatever edit you deem necessary.


Q: What is the advantage or disadvantage of “Simplify” versus changing the level of details?

As mentioned previously, changing the level of details should only be done prior to edits. Polygonian takes a holistic view of the image and tries to achieve a proper abstraction based on user's preference. In many cases this is more than sufficient, but sometimes you may want different levels of abstraction in different parts of the artwork, particularly if you are making a portrait. In this case, you may want to start with a level of details that highlights the important features, and then simplify away regions that are less interesting. “Simplify” does not work the same way as changing the level of details; sometimes one works better than the other.


Q: I already paid for the app, why do I have to pay more to use the Pro features?

Prior to Polygonian, if you are interested in creating high-quality low-poly artworks (try searching for “low poly tutorial”), you are expected to already own Adobe Photoshop or Illustrator (or both) and be ready to spend hours to create a single artwork. Or if you were to hire an artist to do it for you, the quotes would be in the three-digits. You may also consider some of the existing triangulation apps, but perhaps save yourself the trouble by reading how underwhelmed people are in their app reviews.

The truth is, creating high-quality triangulation artworks is pretty much out of reach for the majority of users.

And then Polygonian was created, and it was created as a premium tool, with quality in mind, with its powerful automation as well as rich and responsive editing capabilities certainly. You can use Polygonian to make artworks that are more gorgeous, striking, and powerful than can be done manually (because you can focus on the important details and let Polygonian do the rest). As such, I could have offered Polygonian strictly as a professional tool, at a premium price.

Instead, I chose to offer the standard features at a reasonable price so users of all ages can enjoy this wonderful artform. I reserve the advance features to professionals who want a little bit more at the premium subscription level (higher-resolution images, SVG format, and Portfolio).

That said, the standard version gives you the same powerful automatic engine and full-featured editing tool, and makes high-quality triangulation artworks just the same. It is a great bargain if you ask me. Polygonian also offers a Single-Artwork license at a reasonable price if you need just one artwork.


Q: Can you describe what is available in the Pro subscription?

(1) Save the artwork in PNG format in the highest available resolution (16,000,000 pixels). You can print the artwork at a much larger size

(2) Save the artwork as SVG vector graphics with unlimited resolution. The SVG can be imported into Photoshop, Illustrator, and many other tools for further editing

(3) Offer a complete artwork license for commercial use

(4) Save completed artwork in your own portfolio to be retrieved later. The complete history of each artwork starting from the first moment of triangulation, include the complete Undo/Redo stack, is preserved


Q: Do I own the copyright to the Polygonian artwork?

To the extent that you own the copyright to the source image, yes. If you don't own the copyright to the source image, then you need to check to see if you can do that as “Fair Use”. The copyright law is complicated and you'll need to decide on your own.


Q: Can I use the Polygonian artwork for commercial purpose?

Subject to the answer to the previous question on copyright, Polygonian does not make any claim to the artwork you created. However, if you are using the artwork for commercial purpose, I strongly recommend getting at least a Single-Artwork Pro License, which not only gives you higher-resolution PNG format, SVG vector, but also the ability to save and retrieve the artwork from the Portfolio. Once an artwork is in the Portfolio, so you can reproduce, re-edit, and reuse in the future.


Q: Is there another way of getting the maximum-resolution or vector SVG artwork without the Pro subscription?

You can buy a single artwork license using inApp Purchase. Not only will you gain access to the maximum-resolution artwork and the vector SVG artwork, your artwork will also be saved into your Pro Portfolio so you can retrieve (and re-edit) it anytime you want!


Q: What image formats are supported?

Polygonian supports JPG and PNG formats as input, and JPG, PNG, and SVG formats as output. If you have a Standard License, the artwork is saved as a JPG at 80% compression with 2 to 3 million pixels.

If you have a Pro License (Subscription or Single-Artwork), the artwork can be save as a PNG with 16 million pixels, or in SVG vector format.