What makes a good drawing app?

The UI of Line Brush and a sample artwork.

I've been experimenting with nearly 20 drawing apps for iPad. Of course none of them are perfect and I have a hard time to say one being better than the other. If possible I'd like to make a hybrid app by combining them or more of them but for now the only thing I could do is listing the features I'd want to have in my dream drawing app (I will not talk much about specific painting tool/brush but mostly the core features).

10 must have features on my dream drawing app:

  1. Unlimited layer support. A good drawing app should not only have layer support but also could have unlimited of layers. I understand that some apps set the limit due to the small RAM but believe it or not there are apps that offer less than 10 layers. I usually work with up to 20 layers so I think 10 or below is very restrictive.
  2. Layer merge/duplicate. Not only having layer support is a must, an app also should allow layers to be merged, especially when it can only offer limited number of layers. Duplicating layer also is useful since it would allow a user to do multiple 'version' of the original sketch while making the original sketch intact, without having to make a copy of the artwork itself. Making a copy of the original artwork for the sake of making a different version of it is not always a good solution because a user might want to merge the layers, unless merging 2 artworks is made possible.
  3. Layer/Brush effects. This is one of the most powerful feature in Photoshop. Sure it would add the complexity for the app but that's what makes Photoshop the best graphic software out there.
  4. Dynamic inking tool. If you have tried Paper by 53 you will notice that the width of the line drawn with the fountain pen tool dynamically changes with the speed of the finger movement. Slow movement will let you draw a fine line and for a thicker line you will have to use a faster movement. This is useful when the painting tool offer very little adjustment for the brush size.
  5. Adjustable tool size/opacity. This is pretty much self explanatory and apps that are deemed as 'good' are usually have this feature.
  6. Grid/guide support. This is maybe optional but having a grid or custom guide for drawing would be useful when you are dealing with detailed painting. Having isometric grid would be a bonus too as it would make it easier to draw 3D-ish painting.
  7. Ability to save a copy/duplicate of an artwork. This can work in two environments; either load the artwork first and save a copy of it or go to the gallery and have the 'duplicate' button to do the job.
  8. Cloud storage. Although I have always maintained that I hate cloud computing (especially after what happened to Aviary vector graphic web app) I found the cloud storage is quite useful especially in the event of hardware failure, of which the cloud would make your saved artwork recoverable. AutoDesk SketchBook Pro have this feature and it have saved me many times. An app may offer this as a premium feature while keeping the the app free. However the app doesn't have to have its own artwork hosting service. For me I'd prefer the app to have Pixiv or DeviantArt integration for artwork hosting.
  9. Collaborative drawing. By utilizing the cloud computing this could be a killer feature for the app. So far I haven't seen this in any offline app so I hope my dream app would be the first one to have it. Of course a project moderator is needed to commit all the changes made (in a similar way open source software is being made). After all different artist may have different skills so by combining those it would result in an awesome artwork. Also just like the cloud storage, this feature also may be offered as a premium feature.
  10. Vector tools. Of course no drawing app would qualify as the best app without a decent Vector authoring/editing ability. It's a pity that AutoDesk SketchBook Pro doesn't have the feature although the desktop version used to have the it. Vector editing would bring any drawing app to one level higher than any rival that doesn't have it and at the same time would allow more advanced feature such as gradient fill and object rotating possible.
For me the best customizable ink tool is available in AutoDesk SketchBook Ink but it lacks the layer merging ability present in SketchBook Pro. Also despite it is has only inking tool, it doesn't offer the dynamic inking found in Paper by 53. The best brush effect however belongs to ArtRage Pro while the best layer effects can be found in Sketch Club. Anyway if you ask me the the tool I really want to see in ANY drawing app, it would be the sketchy brush found in Finger Sketch. So far only the sketchy brush in Sketch Club being the most similar to it but even that is still far from what Finger Sketch could do.

Drawing app I've use/tried so far (random listing, not ranked):

  1. AutoDesk SketchBook Pro
  2. AutoDesk SketchBook Ink
  3. ArtRage Pro
  4. Line Brush
  5. DrawSomething (by Zynga)
  6. Paper by 53
  7. FlipInk
  8. Sumo Paint
  9. Inkist
  10. Sketch Club
  11. MyBrushes Pro
  12. Inspire Pro
  13. Finger Sketch
  14. Concepts (vector drawing)
  15. PenGo
  16. ArtPaint
  17. DrawCast
  18. OmniSketch
  19. TouchSketch
  20. Paint Studio