re:
> Hm, on second thought I don't completely understand the explanation from the faq when looking at
> this concrete demo shape. For this example I cannot select any points at all.
Can you please post the .3dm file of your demo shape? Then i can point out the areas to you that are preventing it from having surface control points turned on.
But yes for a case like that it would probably be better to cut the circular hole inside MoI by drawing a circle and using Boolean difference, rather than doing the boolean in polygons in Blender.
Edit: Did a fast test: just removed the boolean intersection thing, now I can select all the points. So this part seemed to somehow inherit to everything?
Edit2: Readded the boolean intersection - this time via a clean extruded circle from within MoI as you suggested. (Works great!) The result is the same though - as soon as this cut is in, I cannot show any points anymore. Also added that one (oddshape3-3dm). might be easier to analyze from within MoI.
Hi, wanted to see the points in order to rescale stuff (e.g. making the blocky end thing shorter etc.) This was just an example, the usual usecase would be direct editing of stuff with precise dimensions.
Thanks for the animation, I still don't completely get what's going on :)
But I also don't want to waste your time as this is hypothetical at this point. Michael already gave me the advise I needed.
Edit: Ah, now I got what you did, you selected everything and then clicked on separate, so all faces are separate objects now. On first glimpse this occured a little bit radical, but with box-selection (selecting all the overlapping points) one can indeed change the geometry of the shape that way. And then rejoin stuff once done. Thanks, this could come handy in some cases!
Hi Nan, thanks for posting the .3dm file. So yes the thing preventing that from having surface points turned on is the hole area here:
If you select that face and use Edit > Separate to break it apart from the main object so it is an individual surface not joined to any other surface, you can then turn on the control points for the face's "underlying surface", which is a larger plane surface:
The "natural edges" of the underlying surface are these:
An edge like this is a "trim edge" - an edge that belongs to the trimming boundary of the face that marks different areas of the face as being active or being trimmed away:
When faces are joined at a trim edge like this internal to the face then you won't be able to turn on surface control points. You can only do that when faces are joined at natural underlying surface edges.
Turning on and editing surface control points is not a major focus area for how modeling in MoI functions. Instead of trying to edit surface points the strategy in MoI is more focused on working with 2D profile curves and doing boolean operations, not on squishing 3D surface points around as it is in sub-d modeling.
re:
> Edit2: Readded the boolean intersection - this time via a clean extruded circle from within
> MoI as you suggested. (Works great!) The result is the same though - as soon as this cut is
> in, I cannot show any points anymore. Also added that one (oddshape3-3dm). might be
> easier to analyze from within MoI.
Yes, that's correct and normal - you end up with the same situation where you have 2 faces that are joined at an internal trim edge rather than at edges of the underlying surfaces.
That's why you generally don't work in a CAD program by turning on surface control points like you do in a poly modeling program.
The way objects are structured in a CAD program using "underlying surfaces" with trim boundaries on them marking active and inactive areas of the surface means that you cannot move 3D points around like you do in a poly modeling program. Poly modeling programs do not have this concept of "underlying surface" and "trim boundary".
Although these structures take away the ability to squish around 3D points like you do in poly modeling, the thing that they give is much better boolean operations because when 2 objects are booleaned in a CAD program it does not have to fragment things into little pieces, the surfaces stay the same and only new trim curves are created on the surfaces. it's fundamentally why booleans work better in CAD programs than in poly modeling programs.
Ok, so the face dimensions are much larger, so it doesn't only affect the local area but the entire object? (Different from the example in the faq, where unaffected points of the same object were editible?).
Thanks for the illustration! Think the current level of understanding is ok for me - I can work with this! :)
re:
> Hi, wanted to see the points in order to rescale stuff (e.g. making the blocky end thing shorter
> etc.) This was just an example, the usual usecase would be direct editing of stuff with
> precise dimensions.
MoI is actually not very good at direct editing of stuff after you have constructed it.
It has a lot of functionality for making things with precise dimensions while you are drawing it, like you can enter in lengths, widths, radius values, etc... while you are drawing curves to get a precise shape right when you initially create things.
But editing of things that have already been constructed is a different area and it's not something that MoI handles very well right now.
There are some other CAD programs that can do that better, SpaceClaim is a pretty good one for what is called "direct editing" in CAD, or also check out Fusion360.
Ok, thanks, might play around with those. Being focussed, doing one thing really well is probably one of the biggest advantages of MoI :)
Edit: Oh, SpaceClaim is a little outside of my budget I fear... But for a start Blender with the Construction Lines plugin is probably good enough for mesh stuff.
> Ok, so the face dimensions are much larger, so it doesn't only affect the local area but the entire object?
Yes that's correct that the dimensions of a face's "underlying surface" can be much larger than its current active area. You'll get that when you do things like booleans. After the boolean is done the surfaces all stay the same and they get new trimming boundaries on them.
When you pull around surface control points in a situation like that then it's pretty easy for the modified surface to no longer intersect with the other ones that it was intersected with to produce the current trim boundary.
So usually in CAD programs you do not form things by moving around surface control points as you do in a poly modeling program.
You can do it in some areas but not just anywhere.
> (Different from the example in the faq, where unaffected points of the same object were editible?).
Well it's the same as in the FAQ - the FAQ shows how editing control points on a plane where there was an edge formed by the intersection between the plane and a cylinder will open up a gap.
oddshape.3dm
