I don't know if I am doing something wrong, but object center snap is not working. It is activated in the object snap properties.


edit: Does it only work on lines that are not part of the objects?

Hi Val - it will only grab the center of certain shapes like an arc, circle, ellipse, or a polygon made up of line segments.

The thing you're trying to snap to must not have any of these exact shapes. It's not too hard to have a curve that looks fairly circular but is actually just a freeform curve that isn't close enough in shape to a circle to have the center snap activated for it.

- Michael

Hi, Michael
Is it possible to have this feature in 2.0 for non circular non straight lines? Or is this something that just cannot be coded?

Hi Val, well it is just not quite well defined what the "center" of a wiggly arbitrary curve is.

Do you mean the center of the bounding box around the curve?

For a closed curve, the centroid of mass as if the curve was a solid plate of material?

The center of the curvature circle at a particular point of the curve?


> Or is this something that just cannot be coded?

There are several problems with coding it. Not so much in just doing the calculation, but rather in coding it to work quickly so that things don't slow down a lot. Some of the above calculations can be time consuming to calculate.. Even the center of the bounding box can be a bit tricky if you want to get a very accurate "tight" bounding box that hugs exactly against the shape of the curve. It's possible to do an approximate tight bounding box quicker but I worry about using approximations in snapping points.

On a larger model it would be hard to avoid things freezing up until all these center calculations were finished.

The basic problem is that the center can be quite a distance away from the actual outline of the curve shape itself, so it is hard to postpone doing the calculations - with some stuff like intersections I can postpone calculating the intersection until your mouse moves nearby the curves that are involved. But I can't really tell if your mouse is nearby the center without doing the full calculation to determine the center...

- Michael

But what I might be able to do in future versions is add some commands that would calculate a point object at one of these "center" locations. Once you created that point object, you could then use it as a snapping target.

- Michael

Everything you said is right on.

It would be very helpful to be able to make reference lines, or even smart track.

thnks

Hi Val - for making reference lines use the "Construction Lines" feature.

This is enabled when you are in a drawing command by pushing the mouse button down, then holding it down and dragging away, instead of a push and release.

When you hold down and drag, you will create a construction line which can be used for snapping purposes like alignments with an edge, extensions, intersections, etc...

For more information, see the doc file here: http://moi3d.com/beta/moi_command_reference2.zip , under the topic "Construction lines".

One really nice thing about MoI's construction lines are that they don't jump up completely automatically - stuff that is triggered automatically can tend to get frustrating and get in your way when you don't want it. With a construction line, it is only triggered with that dragging gesture so it stays out of your way until you call on it, but it is also really easy to call on.

Also other kinds of reference line things are usually limited to radiating a line out from one single point, just along major axis directions. With MoI you get to choose 2 points for the reference line, the spot where you clicked down on, and then the point that you released the button up on.

Since your line is defined by 2 points (instead of one point + axis directions) you can have it angled at any direction, and this also gives many other abilities like finding the midpoint between any 2 points by using a construction line, doing mirrored points, setting up divisions like 1/5 increments between 2 points, capturing a distance and applying it to a different location, and more... This is all covered in that doc file above. Also see the new tutorial video here: http://moi3d.com/forum/index.php?webtag=MOI&msg=975.1 , it uses construction lines in it as well.

- Michael

crap! how did I miss that lol. This will help me a lot. Thank you! I like it way better then sketch up's and rhino's. No, really it is awesome.

here is what I got so far. The whole thing is actually only about 1.5% done. This is only a part of the final model :D

Hi Val, well that's one of the downsides of making something that stays out of your way until you trigger it - it isn't so obvious at first that it is there...

But I hope to improve that by some of the video tutorials that I will do.

Cool model, it looks interesting! I hope you'll post the final version too.

- Michael

Thanks!
I will post every part as I finish them including the final. I think I will do a small tut on some of the bottle necks of the process, and techniques.

I originally began modeling this in blender, but I scraped the model and decided I needed to use NURBS to make nice smooth surfaces, that are car like in design. Modeling what I got so far using polygons would be a nightmare!

Michael,

Hi.

Is the 3D view parallel projection? Is it possible to change it to perspective?

Val

Hi Val - the 3D view is perspective already.

- Michael

Sorry, that was a stupid question.