Hi Michael,
yes I know of these features, this is how I position background images. However it is still trial and error, and takes a few trials to get it right.
I would like to be able to scale by 2 point click, and also rotate them in a similar way as other objects (and not wiht the grips).

The problem is that right now I am working with the frame of the image, which is fine if there is another reference frame, but say I have as a reference in the drawing which i know is 20m long, it would be nice to be able to just draw a 20 m long line in moi, and then snap the image to this, and do a scale operation by snapping to the line object (this is how it works in AutoCad for exemple)

Hi okapi, unfortunately it is tough to make the regular tools work on images - the regular tools work on the selected objects.

If you could select images as you could normal objects, they would frequently get selected instead of the objects that you are working on since they take up a large area of the screen. They would just easily get in the way of operating on your objects.

You might try creating a rectangle or line curve as a reference object, scale it to the exact size that you need and then snap on to it when scaling the image.

If you create that guide line initially before you even place the image, you should be able to draw the image in at the correct size when you initially place it.

- Michael

Hi Michael,
I think it is good to have a special mode to modify the images, so that they don't get in the way as you mention.
I just sometimes wish I would have a quicker way to scale the images in relation to a given line or square in the scene.

Hi okapi - maybe I don't understand the problem, you wrote:

> I just sometimes wish I would have a quicker way to scale
> the images in relation to a given line or square in the scene.

You should already be able to do this, when you drag the corner of an image snapping is enabled to any given line or square in the scene, unless you have possibly turned off Object Snap in the bottom toolbar? If you look at the bottom toolbar, the Object Snap button should be highlighted in orange to enable it.

Here is a quick demo that shows how you can snap an image to an given line or square in the model using object snaps:




Doesn't that do what you need? If not I guess I need some more details.

- Michael

Hi Michael, this is how I position Background images at the moment.
The problem however is that quite often the background image I have (let's say a Cad plan printed as a PDF, then saved as an image)
does not have a precise length and width.

The precise information I have is the drawing itself. So in your exemple, with the car, it would make more sense for me when placing the image if:

- I drew a line that is 4 meters long (or however long the bottom edge of the chassis is)

-Moved the image by clicking on the image on one point of the equivalent line at the bottom of the chassis, then draging and snapping the the equivalent point on the line.
-Then scale the image by clicking on the same point again, clicking on the other extremity of the bottom edge of the chassis (on the image) and scaling down, by selecting again the other equivalent point of the line.
Just like I would If I had a reference nurbs object, and I wanted to scale down another object to fit exactly to it.

Basically, sometimes it does not makes as much sense to use the edges of the drawing as reference to place an image, it would be better if I could click somewhere on the image.
Maybe it is not clear, if I find a small break today I can generate a gif showing what I mean.

Hi okapi - ok thanks for explaining it more, I understand now what you mean.

You should be able to do the first stage, the positioning part, currently - you don't have to drag on a corner of the image, you can drag anywhere inside of an image to move it around to adjust its position.

It's the second part of matching the "registration marks" between the image and the model which is a problem.

It will be difficult to make the regular scale tool work on images, since an image is just not set up to be treated like a regular object. It just does not fit within the regular object and selection mechanism which is what the normal scale command is designed to work with.

But maybe what I can do is add a "Scale" button into the View / Image command to handle this particular image task - there is a pretty good spot for a button under the "Add" button in there right now where it could go.

Do you need to align a rotation in a similar way? Maybe instead of a "Scale" tool it should be an "Align" tool which does scaling and rotation both by picking 3 points.

- Michael

Hi okapi, how about something like this:



That will let you pick 4 points to do image registration - you pick a base point and reference point on the image (you'll probably want to zoom in there, I didn't do that to keep this screen capture small), then pick a target base point and target reference point snapped on to your geometry.

It will then do a combination of move, rotate, and scale to make the image aligned and sized to the right amount to align with that geometry.

- Michael

Hi Michael,
this is great!
This is even better than what I had in mind, since you take care of the whole alignment (scale and rotate) at once.
If it would be possible to add this to Moi, it would be a huge help when working with references.

Hi okapi, I'm glad that will work for you - yes I should be able to add this in for the next beta which should be ready pretty soon. That was actually a screen capture of it working inside of MoI right there.

It will be a new button that will show up here:



When you have multiple images, the one that will be edited is the one that is highlighted in the list, so that part is a little different than dragging images.

- Michael

This is excellent.

Many times in blueprints you have exact dimensions for wheel base, total length, etc.

What a time saver!

This alignement will also valuable with the normal Edit frame box?

Hi Pilou - no not currently, as you can see in this post here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1982.11

it is actually a special part of the Image command that you activate by pushing the new "Align" button in the Image options panel.

It isn't activated by doing anything on the edit frame, it is a totally separate thing from that.

I do want to add an additional kind of align/orient tool for objects as well though, but again it will likely be a new transform command and a separate thing from the edit frame.

- Michael

thx for the precisions :)