Curve draw tool's cursor depth mode use a random Z value when viewport camera is orthographic #101347

New Issue

System Information
Operating system: macOS-12.5.1-x86_64-i386-64bit 64 Bits
Graphics card: Intel(R) Iris(TM) Plus Graphics OpenGL Engine Intel Inc. 4.1 INTEL-18.8.4

Blender Version
Broken: version: 3.3.0, branch: master, commit date: 2022-09-06 15:39, hash: 0759f671ce
Worked: N/A

Short description of error

When drawing a curve at Top view, using Cursor Depth mode, my expectation is for a spline to appear at XY plane, at cursor's world space Z position; but what actually happens is a spline on XY plane with a random Z value, this issue happens when my viewport camera is in orthographic mode.

I wasn't able to reproduce this issue immediately with a new blend file, but it does fail in my uploaded blend file example, and I have experienced this many times in recent usage, suggesting some unrelated settings might have trigger this problem.

(If this is by design, the manual page need to go much deeper explaining this behavior, I certainly couldn't figure out how it works myself via googling.)

Exact steps for others to reproduce the error

draw-curve-bug.blend

Download attached file, go to Top view and try to draw splines in orthographic view and perspective view respectively, and observe the spline has a random Z value when drawing in orthographic mode, while perspective mode gives you a spline at Z = 0 correctly.

**System Information** Operating system: macOS-12.5.1-x86_64-i386-64bit 64 Bits Graphics card: Intel(R) Iris(TM) Plus Graphics OpenGL Engine Intel Inc. 4.1 INTEL-18.8.4 **Blender Version** Broken: version: 3.3.0, branch: master, commit date: 2022-09-06 15:39, hash: `0759f671ce` Worked: N/A **Short description of error** When drawing a curve at Top view, using Cursor Depth mode, my expectation is for a spline to appear at XY plane, at cursor's world space Z position; but what actually happens is a spline on XY plane with a random Z value, this issue happens when my viewport camera is in orthographic mode. I wasn't able to reproduce this issue immediately with a new blend file, but it does fail in my uploaded blend file example, and I have experienced this many times in recent usage, suggesting some unrelated settings might have trigger this problem. (If this is by design, [the manual page ](https://docs.blender.org/manual/en/3.3/modeling/curves/tools/draw.html) need to go much deeper explaining this behavior, I certainly couldn't figure out how it works myself via googling.) ![Screen Shot 2022-09-25 at 11.28.34.png](https://archive.blender.org/developer/F13567124/Screen_Shot_2022-09-25_at_11.28.34.png) ![Screen Shot 2022-09-25 at 11.28.44.png](https://archive.blender.org/developer/F13567122/Screen_Shot_2022-09-25_at_11.28.44.png) **Exact steps for others to reproduce the error** [draw-curve-bug.blend](https://archive.blender.org/developer/F13567042/draw-curve-bug.blend) - Download attached file, go to Top view and try to draw splines in orthographic view and perspective view respectively, and observe the spline has a random Z value when drawing in orthographic mode, while perspective mode gives you a spline at Z = 0 correctly.

Added subscriber: @Zhen-Dai

Added subscribers: @ideasman42, @mano-wii

Changed status from 'Needs Triage' to: 'Confirmed'

I can confirm the problem.
Apparently the problem is because ED_view3d_win_to_3d_on_plane doesn't work properly when the do_clip option is true and the view is orthographic.

(Tagging @ideasman42 as the operator was introduced in 8ac662c77a)

I can confirm the problem. Apparently the problem is because `ED_view3d_win_to_3d_on_plane` doesn't work properly when the `do_clip` option is `true` and the view is orthographic. --- (Tagging @ideasman42 as the operator was introduced in 8ac662c77a)

@mano-wii Is there a way to disable do_clip option that you mentioned here? I would like to use cursor depth mode because surface mode cause my geoemetry to z-fight with the surface draw on.

@mano-wii Is there a way to disable `do_clip` option that you mentioned here? I would like to use cursor depth mode because surface mode cause my geoemetry to z-fight with the surface draw on.

This issue was referenced by 93bbaad2f8

This issue was referenced by 93bbaad2f8dfaf5a141e79c5e976fd16226ef4af

This issue was referenced by 2004827bc9

This issue was referenced by 2004827bc990708117548c77337af13603efb37a

Changed status from 'Confirmed' to: 'Resolved'

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Curve draw tool's cursor depth mode use a random Z value when viewport camera is orthographic #101347