Hello,
Boy, this one drove me nuts. I was trying to take an image, crop it into 2 images, then use one for the front and one for the side for modelling reference. I could not for the life of me get the images to align vertically in the SOPs viewport. As it turns out, the size of the horizontal crop affected it!! That's really, really terrible.
Please see attached. In this case, just using a ramp which is pixel-perfect of course, you can very easily see that the side view is “taller” than the front view. If you adjust the crop nodes (the first set, doing the horiz crop) and make sure the images are the same resolution, then the BG images in SOPs line up. That's really bad.

Cheers,

Peter B

Houdini takes a background image, determines the short side and scales the image so that the short side attains a certain size. The reason for this is to maximize the background image coverage. In your case, one image happened to have a shorter width than height, and the reverse was true for the second image. Hence, image one was uniformly scaled to match the width and the second image was uniformly scaled to match the height.

You would not have experienced this problem if both images had shorter widths than heights or shorter heights than widths.

Nevertheless, I have submitted an RFE (ID=20973) for a menu to add options to scale by:
1. short side (currently only option)
2. long side
3. horizontal side
4. vertical side

A better RFE would be for 2-D scale and offset parameters.

There are parameters for image offset and scale (3D Viewport sub-tab), but in order to use them, “Automatically Place Image” must be off, and good luck getting those parms set properly!

It would be nice if Auto-Place Image set the offset and scale to the current auto settings, so if you turn it off, the BG image doesn't jump and you can fine-tune the position.

Hi guys,
Thanks for the info. Something's gotta change, ‘cause it’s pretty flakey the way it is right now. The “autoscaling” of the shorter side is, frankly, awful. Unbelievably unintuitive and in my case, made the BG image stuff unusable. Anytime software tries to “auto” something, it inevitably causes problems!! Now that I know what the problem is, I can work around it of course. Naturally, there is exactly 0 documentation on this. (
There should be a pixel for pixel mode, and if you want to squeeze it or do other strange things, do it yourself in COPs, or in Photoshop and load the Jpg in, or whatever. Please add the RFE for “don't f*&k with the image” mode, which should also be the default to prevent people wanting to shoot Houdini (again). Documentation is good too )
Mark's idea for the Autoplace setting offset and scale is good too, if I could see that it was scaling the image numerically, I would have figured out the problem a lot sooner.

Cheers,

Peter B

“Maintain aspect ratio” seems like a good candidate for a button here. Agreed, it's got the mystery mojo going for it as it is.

Cheers,

J.C.