Call for Testing: 2-Point Perspective Assistant

Develop Artists Feedback & Testing
#1

Hi all, I have been working on a new painting assistant in Krita to do easy 2 point perspective drawing with the Freehand Tool.

It is mostly complete and you can try it now tomorrow in the Krita Next nightly builds (unstable!!). I’m looking for feedback on the control scheme and appearance to make it ready for mainstream use and also suggestions for future enhancements to make, so please take a look :smiley:

2021-04-08-08:06:17
2021-04-08-08:06:17798×695 50 KB

If you come from other digital drawing programs or have used perspective grids tools before then this one will seem familiar, indeed, Krita already has a Vanishing Point assistant that is already very handy on it’s own, this one is similar.

For those unfamiliar with Krita’s painting assistants feature, here’s how to use it:

  1. in a new document, switch to the Assistant Tool
  2. make sure “2 Point Perspective” is selected in the drop-down menu in the Tool Options.
  3. click somewhere to the far-left of the canvas to place the first vanishing point, then click somewhere to the far-right to place the second vanishing point
  4. click somewhere in the middle of your page to finalize the assistant with a third control point
  5. switch back to the Freehand Tool then mark the “Snap to assistant” checkbox in the Tool Options
  6. draw a box :slight_smile:

Counter-intuitively, the Two Point Assistant is made of 3 control points! The noteworthy value proposition that this set up offers is the following:

  • It draws a grid that accurately visualizes the effect of perspective distortion
  • It is capable of moving both vanishing points at once in such a way that preserves the effect of perspective distortion

Here’s the current control scheme:

  • When creating a new assistant, Shift-click to snap a VP to a vertical or horizontal axis
  • Ctrl-drag a VP to preserve perspective distortion. This will cause both VPs to move along the horizon line in the same direction which rotates the grid. Distortion is “preserved” in the sense that when you let go of the VP, every place on the canvas appears is as distorted by perspective as before, the grid is just at a different angle.

  • Ctrl-Shift-drag a VP to preserve “yaw”, this is the left-right direction of the VPs, and will cause both to move closer or farther from the center point. Moving VPs this way is pretty much like zooming in/out or increasing/decreasing FoV

  • Alt-drag a VP to move it freely along the horizon.

Let me know your thoughts!

15 Likes
#2

Please, all testers:

2 Likes
#3

I will like having such a thing on krita, it can help a lot with giving a see of 3D on drawings.

#4

It’s already implemented and merged to master (dev version). Now you can test it and see if there are any issues.

1 Like
#5

The Nightly with these changes failed to build, though.

#6

The build failed. :sob:

#7

Is there gonna be 3 point perspective assistant as well with this concept?

Also I think renaming Vanighing Point assistant as ‘1-Point Perspective’ afterwards to align with the other 2 would be good.

1 Like
#8

I haven’t actually tested yet as the nightly build seems to have failed, as others noted.

A suggestion, though: I think it’s possible to let the user input 35 mm equivalent focal lengths and calculate the distance between the vanishing points from that. This could be really useful.

#9

Also I think renaming Vanighing Point assistant as ‘1-Point Perspective’ afterwards to align with the other 2 would be good.

I don’t really agree with this because there are other uses for single vanishing points in a scene, for example drawing a staircase or hill road, or drawing an object that is out of alignment with the rest of the scene.

1 Like
#10

I will test this tomorrow, I think more options can be interesting :thinking:

#11

I also want to know this.

#12

Yes! I’ll eventually work on it, I prefer 3pp drawing anyway.

Sounds handy but truth be told I don’t actually know how to calculate FoVs from a given focal length as I’m not familiar with photography … also the distance between the VPs would have to depend not just on focal length, but how big the user intends to draw, if they’re making a comic it would only be a portion of the canvas.

Right now you can already tell how big the 90 degree FoV is by the gap between the points that the grid rotates around (I’m not sure what focal length a 90 degrees FoV corresponds to):

(NB there’s a bug where this gap will occasionally “drift” and increase in size, it should remain fixed)

Yeah Krita’s Vanishing Point assistant is surprisingly versatile on it’s own, and I suspect many people will prefer it because it’s more flexible. I don’t intend to obsolete it, instead I might develop a “1 Point Perspective” assistant that lets you specify horizon tilt and draws an accurately distorted grid, it would have to be made with 2 control points to achieve this.

2 Likes
#13

Yeah Krita’s Vanishing Point assistant is surprisingly versatile on it’s own, and I suspect many people will prefer it because it’s more flexible. I don’t intend to obsolete it, instead I might develop a “1 Point Perspective” assistant that lets you specify horizon tilt and draws an accurately distorted grid, it would have to be made with 2 control points to achieve this.

Yeah, I agree with this. A separate 1-point assistant that draws a proper ground plane would be great, and we can keep the regular vanishing point for other uses. :slight_smile:

2 Likes
#14

Thank you for your work, this is great. :smiling_face_with_three_hearts:

#15

I think that’s the 1 point perspective by definition. Users can put multiple 1 point perspectives in a scene.

#16

Renaming it doesn’t mean removing the vanishing point feature.

I really don’t see any practical difference from the original vanishing point assistant and I oppose the idea of seperating those because it would only mean complication for basically nothing. :neutral_face: If we need any extra feature on 1 point perspective assistant, I think just adding the feature to vanishing point and renaming it to 1 point perspective would be the best.

1 Like
#17

Not quite, 1 Point Perspective is a specific situation where the primary vanishing point of an object or scene is directly on the center of the viewer’s gaze.

#18

You could be right! I still kind of feel like there’s a small distinction there, but as things develop I could figure out that I’m wrong and that we don’t actually need the single VP assistant anymore at all.

One of the great things about Krita is that we can kind of play it by ear, discuss it as a community and see where that takes us. Once the pieces are in place we can decided if we need them both or not, you know?

The more important thing right now is to test out Nabil’s work on the 2-point perspective assistant to see if there are any other changes or improvements we can make before Krita 5.0 ships later this year. :slight_smile:

#19

I can’t test this right now . It says build has failed. :frowning:
https://binary-factory.kde.org/job/Krita_Nightly_Appimage_Build/

Anyway my first impression (as i have seen in the videos) seems to be really easy and fast to be used. A gift for “fast setups” in concept art… And can be completed with the vanishing point assistant if you need more VPs. I can’t say more without testing. But thanks for your effort really. For me is a “please continue” :smiley: :clap: :clap:

Things to be considered. Colors are important when you have zoomed and have a bunch of lines. Also precission with little angles to avoid the Ctrl+z too much usage while drawing. (i know this is also related with the speed and skill of the stroke)

Have you considered to include features like Rulers?
https://lazynezumi.com/ shows in Rulers section something that maybe more users can be interested in.
If we want to translate divisions to a surface like i did in the last video manually.
https://youtu.be/FobRbvuzsnI?t=867

By the way Lazy nezumy works with Krita (only in Windows) and has interesting features for the people who needs extra things. ( i am not exponsored by them. i just give the info :wink:

1 Like
#20

The recent Apr09 #1302 Windows build completed with no problem and is here:
Krita_Nightly_Windows_Build [Jenkins]

The Linux appimage should be available in about six hours from now.

The ‘2 Point Perspective’ is present and seems to be working nicely.
Thank you @NabilMaghfurUsman :slight_smile: :slight_smile:

I think there is some roughness with snapping but I don’t have time right now for a detailed look at it.
I’ll make more observations about this later.

Sadly, many main menu items are missing.