Draft Workbench - how do I set camera position?

[rhombus]

I'm building a floor plan in Draft Workbench. I intend to pad the walls in 3D.

I have some faces which will be lintels for doors. The faces are at different heights. When I set the working plane to XY, only some of the faces are visible. I'm assuming this is because the camera is at a certain height and some of the faces are behind it. When I rotate the view, the faces appear:

Here's the camera view with XY set as the working plane:

camera1.png (152.43 KiB) Viewed 1586 times

And here's the camera view when I rotate the camera a little:

camera2.png (237.3 KiB) Viewed 1586 times

You can see that the face which becomes visible is at z = 2.6 m. (The other face that is always visible is at z = 2.3 m, so I'm guessing that the camera plane is at z = 2.5 m.)

How can I explicitly position the camera when using standard working planes? (Note that this question is not about changing the working plane, I know how to do that.)

OS: Gentoo/Linux
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.Unknown
Build type: Release
Python version: 3.6.5
Qt version: 5.12.3
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: German/Germany (de_DE)

[chrisb]

Try macro FCCamera from the Addon manager.

[Roy_043]

In my test using Std ViewFitAll is effective.

[vocx]

...
You can see that the face which becomes visible is at z = 2.6 m. (The other face that is always visible is at z = 2.3 m, so I'm guessing that the camera plane is at z = 2.5 m.)...

The camera is not at 2.5 m. Simply put, this is a rendering issue with the 3D view (or Qt or Coin3D or OpenGL or your graphics card or something). It's a "bug", if you will, but it's hard to really know how to solve it because there are many libraries involved.

The easiest thing you can do is to ignore it, and yes, do rotate the view around to see the different shapes. With 0.19 there are better selection tools, so when you pick objects in the tree view they are highlighted in the 3D view; this will improve things like these, making it easier to recognize where your objects are.

[rhombus]

...
You can see that the face which becomes visible is at z = 2.6 m. (The other face that is always visible is at z = 2.3 m, so I'm guessing that the camera plane is at z = 2.5 m.)...

The camera is not at 2.5 m. Simply put, this is a rendering issue with the 3D view (or Qt or Coin3D or OpenGL or your graphics card or something). It's a "bug", if you will, but it's hard to really know how to solve it because there are many libraries involved.

The easiest thing you can do is to ignore it, and yes, do rotate the view around to see the different shapes. With 0.19 there are better selection tools, so when you pick objects in the tree view they are highlighted in the 3D view; this will improve things like these, making it easier to recognize where your objects are.

When I made a face identical to the left face but placed at z = 2.2 m, it displayed correctly, hence my suspicion that the viewing plane was at z= 2.5 m.

But for some reason, now the face on the left is visible even with XY working plane and Top view. Why it is suddenly working, I have no idea. That would seem to confirm your suspicion of a rendering problem.

Perhaps this possible cause is also what's behind this issue with hatching and dotted/dashed lines? https://forum.freecadweb.org/viewtopic.php?f=3&t=40104

I've seen this kind of thing happen with other visualization libraries, in the past it's been an issue with z-buffering, but I don't know if that's the cause here.

I'm using Gentoo, which builds packages from source. Moreover, FreeCAD isn't in the main tree, so I am using a "custom" package from an overlay. I'm using Coin 4.0.0a_pre20181221. Is there a more current version? Or should I be looking for the problem elsewhere? It does make work more challenging, so I would like to solve it if possible.

[DeepSOIC]

As a workaround, adding a wireframe box with a size to accommodate all your design with a bit of margin may help.
Also it sometimes helps to switch camera to perspective, zoom out/fit all, and switch back.

[vocx]

...
I've seen this kind of thing happen with other visualization libraries, in the past it's been an issue with z-buffering, but I don't know if that's the cause here.

I'm using Gentoo, which builds packages from source. Moreover, FreeCAD isn't in the main tree, so I am using a "custom" package from an overlay. I'm using Coin 4.0.0a_pre20181221. Is there a more current version? ...

Yes, this is all Coin's fault (probably). You won't find a newer version of Coin, because the project basically is frozen. It isn't exactly in constant development. As a matter of fact, the last version that Coin developers launched was something like 3.1.3. As FreeCAD needed Python 3 support, some FreeCAD developers ported it to Python 3. This new version became Coin 4.0.0alpha, which was not officially released by Coin3D developers, but in many cases became the de-facto most up to date version. Basically, you have the latest code already.

There are plans to migrate Coin3D to GitHub, so maybe the project is a bit more active nowadays. See Coin3D - FreeCAD Delegation to help move Coin3D forward.