Sorry in advance for the probably basic question:
I have created a solid via the following steps:
* create a rectangle (e.g. 30x20, centered around 0,0,0)
* create another rectangle (e.g. 20x10 100mm away though centered around 0,0,100)
* lofting these two rectangles to get a solid cuboid
* delete the two construction rectangles
Now a little later I decide that I want to change the size of the 30x20 side to 40x20. My attempts so far:
* selecting the solid and clicking on "Show pts." to move the points up - but show pts. isn't working
* selecting the 30 mm long upper edge, trying to drag this up - doesn't move
* selecting the 30x20 face, try using the 1d and 2d scaling tools selecting the base as center, trying to scale the face - nothing happens
The only way how I could manipulate the solid was to use scale on the entire solid. But that way I can only change the overall height, not the height on one side.
Is there something I could do? Or is the only way to do this to throw the solid away and remake it from scratch if I already deleted the lofted original rectangles (or did other operations in between that deleted the history)?
Edit: added the cuboid 3dm for reference. (dimensions are 210x55 and 130x35 and the distance 1000 in this example but the concept is the same. Let's say I want to change the 210x55 side to 200x55)
Edit2: I separated the solid, now I could select the points again. But the control points for the two rectangles weren't on the corners but again a much wider plane. Why can't those just be the corners of the rectangle itself - then show points would probably also have worked? I'm apparently still struggling to get the logics behind some construction steps.
Edit3: Here a second iteration where I manually deleted the faces with the big construction planes and added faces instead. These have the control points as expected directly on it's corners. If I join these faces again, I get a solid where I can edit the points as expected.
Wouldn't it be better if the result of the loft would be something along the lines of this second object? What is the advantage of these big planes?
after lofting it should keep a history(any changes to consruction lines will remake loft)
selecting the solid and clicking on "Show pts." to move the points up - but show pts. isn't working -> Show pts for works for faces (detached from solids)
selecting the 30 mm long upper edge, trying to drag this up - doesn't move -> try to select face & extrude
selecting the 30x20 face, try using the 1d and 2d scaling tools selecting the base as center, trying to scale the face - nothing happens -> detach face if u want so, rework with particular face
The only way how I could manipulate the solid was to use scale on the entire solid -> scale2d/booleans, remake construction line & extrude
Yepp, full scale worked here, too. The separate trick that somebody showed me in another thread worked (just wasn't aware that it was indeed a similar situation). Manually replacing the faces with the big construction planes with faces with normal ones (that are as big as the plane itself) and then rejoining the solid is a good workaround.
I imagine these big construction planes are needed for more complicated lofts? Could these big construction planes perhaps be ommitted in cases where they are not technically needed? (Like in my case where simple faces would probably be sufficient?)
"Rule #1 in MoI: Never delete a construction curve :) Assign it a unique color, then hide it."
Thanks, will keep that in mind! :)
Tried a "best of both world" approach of keeping the construction rectangles and fixing the faces, so the points can also directly be edited. That doesn't work though, replacing the faces deletes the history connection. Ok, nevermind, one way to achieve something is enough.
Hi Nan, really the simple way is to just delete your object and make a new one. You can duplicate some edges to get your construction curves back again, either select the edges and use copy/paste (Ctrl+C/Ctrl+V) to duplicate them or also you can use Edit > Join on an edge selection to make a separate joined curve.
I'll try to answer your other questions though.
> * selecting the solid and clicking on "Show pts." to move the points up - but show pts. isn't working
> * selecting the 30 mm long upper edge, trying to drag this up - doesn't move
You can't move around an edge sub-object in a MoI object, this has to do with edges possibly being trim boundaries on an "underlying surface" - see above link for more description on this.
But basically an edge in Moi does not control the shape of surface geometry, there is an "underlying surface" that defines the surface geometry and edges live on those surfaces marking areas as active or holes.
> * selecting the 30x20 face, try using the 1d and 2d scaling tools selecting the base as center, trying to scale the face - nothing happens
You can't move around a face sub-object for similar reasons as edges.
re:
> Let's say I want to change the 210x55 side to 200x55)
I would probably draw a new 200x55 rectangle on that side, select the 4 edges of the opposite side and use Edit > Join to create a curve out of them, then delete the current solid and make a new one using loft.
re:
> I separated the solid, now I could select the points again. But the control points for the two rectangles
> weren't on the corners but again a much wider plane.
You get those wider planes as the "underlying surface" for anything that generates end caps. Loft is not limited to only work between rectangles, it can be between curved shapes too. When applying end caps the general mechanism for it is that it makes a large plane which is trimmed by the edges of the ends.
If you like you could delete the end caps, then Show pts will work on your object, then when you're done manipulating the points select the whole object and use Construct > Planar to put new end caps on it.
> What is the advantage of these big planes?
It makes for more uniform behavior with generating planar end caps. With curved outlines an underlying plane surface that hugged directly to the trim edges would have a couple of places where the edges touched the edge of the natural underlying surface at a "grazing tangent" point which isn't necessarily outright terrible but it makes for some more work to be done in some kinds of intersection processing.
If you like you can select your cuboid objects, then type Tab and type in ShrinkTrimmedSrf and push Enter. That "ShrinkTrimmedSrf" command will shrink down those wider planes.
>It makes for more uniform behavior with generating planar end caps. With curved outlines an underlying plane surface that hugged directly to the trim edges would have a couple of places where the edges touched the edge of the natural underlying surface at a "grazing tangent" point which isn't necessarily outright terrible but it makes for some more work to be done in some kinds of intersection processing.
Ok, understood. Perhaps a heuristic could be used that only creates the big planes in cases where they are needed? The consequences of having them are a little hard to grasp, particularly for newcomers, questioning oneself why certain operations have no effect.
>If you like you can select your cuboid objects, then type Tab and type in ShrinkTrimmedSrf and push Enter. That "ShrinkTrimmedSrf" command will shrink down those wider planes.
That is a good shortcut to get the object into the shape I want - now show points works! Like with manually replacing the faces with "close fit" faces it removes the link to the construction rectangles - but that's ok.
One can, on more complex solids, also use the "edit frame". And all that we can do with it : resizing and rotating, partially or over the entire surface of the projection plane, etc.. Great!
I ask myself a question, can we have a regular grid? This is not the case in my example (I have to try).
lofted_cuboid.3dm
