How to prevent Zooming with the trackpad (mac) or mouse?

[JxL]

Dear All,

I am trying some fine tuning match between an 3D object and a photo that I put in background with watermark.

But when I move on the trackpad, or touch the wheel of the mouse, even if I dont want to do it, the zoom change on the screen and ruin my efforts.
The zoom si also different when I load a saved work.
The actual size of the object has not changed.

How can I prevent this ?
How can I lock the zoom value ?

[DaveR]

This sounds like a training issue. You need to learn to leave the wheel of the mouse and trackpad alone. While you are working on learning that, set up the camera where you want it and create a scene so you can at least get back to it easily when you forget and roll the scroll wheel. There isn’t a setting to turn off Zoom so you’ll have to deal with it manually.

[colin]

It is true that it can be a bit sensitive. If you’re orbiting and zooming, one work around would be to add a scene. Then work on the view until it’s improved, and use the Update scene(s) button:

If you accidentally throw things off a lot you can click the Scene 1 button at the top of the window, to move you back to where you were a moment ago.

I can’t find a way to make the mouse wheel do smaller jumps in scale, but using the Position Camera, Look Around, and Walk tools, gives you super fine adjustments.

[slbaumgartner]

@colin

I can’t find a way to make the mouse wheel do smaller jumps in scale,

So far as I know, this can only be done by changing the mouse wheel sensitivity in the system, which will of course affect all other apps too. SketchUp does not provide a preference setting for this.

[colin]

Changing the mouse wheel sensitivity won’t help. It does let you scroll slower, but it doesn’t change the minimum zoom jump that SketchUp does, it just takes you slightly longer to get there.

This video shows how smooth the Walk tool can be, and then how jumpy zoom, using the mouse wheel, is:

http://colin.scienceninja.com/zoomy.mp4

Using the actual zoom tool and dragging does give you as smooth a zoom as the Walk tool gives.

[Michael_S]

You could use the Position Camera tool and guide lines to reduce guesswork:

1. Draw guide lines from the image to corresponding points on your foreground object, for a good handful of points. Ideally, the guide lines should converge at the same point, or at least pass through a small spatial region.
2. Pick one of the intersecting (or nearly intersecting) points, and draw a vertical line to the floor.
3. Measure the height of the vertical line.
4. Use the Position Camera tool and put its marker at the foot of the vertical line you just drew.
5. Before doing anything else, enter the length you just measured in the measurement box. This will be the new camera height.
6. Use Look Around to pan/tilt as needed, and the Zoom tool with Shift+mouse up/down to adjust your field of view. Shift is essential to maintain the camera position. (Otherwise, the Zoom tool performs a dolly zoom, i.e., changes both distance and FOV.)
7. Save this view as scene.
8. Delete the guide lines.

Hope this helps!

[JxL]

Thanks to All for this feedback.
At least I understand that it is normal to experience these difficulties with the zoom, and I will try to avoid using the wheel on the mouse.

For the trackpad, it is more difficult, as you can very easily zoom without wanting it while using the trackpad. Just need to have a second finger touch the trackpad.

@Michael,

In my use, I do not place the camera, the observer is at infinity ( parallel projection).