check the vid, basically I dimension one spline acr and with the same dimension values
in a new sketch all looks different - which to my understanding should not
https://drive.google.com/a/ckbrd.de/file/d/0Byzv_NlyKp_2YzFDZlNZdzNyLVE/view?usp=drivesdk
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
Claas, you're right, this is super weird.. I tested it out and I got three different results...
Sketch 2 is referenced to sketch 1. Sketch 3 is completely unlinked but with same constraints and dimensions. All three are different..
They all have smooth constraints to horizontal lines at ends, vertial constains in middle spline control point line, which is colinear to midpoint on the vertical line.
I've attached the f3d below.
@Anonymous
autsch = looks like the sketch engine has a bug here a pretty hefty one
@jiang_peng check Ndenekamps file simple thing to test on your side
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
I played around with this some more, and found that merely putting a dimension of a spline handle (a driven one in fact) changes it..
In the gif you can see the driven dimesnion being added. I then undo and redo a couple of time to show the difference.
It's like the observer effect or something..
Niels
@jiang_peng I did not save that file. But since @Anonymous has the same issue maybe rebuild it or ask him to send you the file.
I did a quick test and it worked this time without a problem.
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
I understand your point and the logic makes sense but it shows that users are confused by how the UI displays data.
So we add smooth constraint. First Fusion does not allow you in anyway adjust the G1 and G2 point position or weight like with cv curves.
I think that is what most non solid modeler users will look for. Alias blend curve is also pretty smooth
In Fusion often the smooth constraint is only step one because they to adjust accelerationa and such you need to add the dimensions.
And with a G2 constraint you can on Fusion only access to the G1 value via the tangent handle.
The problem is that you see the position of the handle and see the shape of the spline so you would assume that with the dimension
added and not changing the tangent handle the spline will remain the shape.
After all the fit curves auto adjust the handles so one can assume that the handle always represents some value to massage the curve.
I hope this makes sense why @Anonymous feels confused when he adds the value.
I cannot wait till the sketch engine has cv curves and aling commands for g0 g1 and g2 like in Alias because I find the spline tool very hard/labor intensive
to use and often it adds needles complexity to a design process.
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
@Anonymous thats why I think Fusion needs a blend curve this spline with handels is not always the best idea. i am very curious how they will to the cv curve implementation
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
Hello Claas and Niels,
Tried this with dimensions 10 times greater, and then these splines appear identical (not an extensive test, I had 5 consecutive identical splines). So it seems that size does matters in this case.
I'm just guessing here but may be some kind of rounding error when the dimensions are too small, of course this should not happen.
With the original dimensions, (10 mm - 1,25 mm - 5,5 mm and 3 mm) it is very hard to end with the same splines, out of 4 I had 2 identical and 2 different ones.
Hope is of any help.
Best regards,
Ludo
In our spline solver, we have a inner ratio parameter which is calculated when the spline is created. So after that, we can drag the fit points to make a smaller spline, but the ratio is not changed. That ratio parameter will also impact spline shape.
I think above step is easiest way to reproduce the problem. I think we need to find an approach which will fix the problem meanwhile will impact current behavior less.
Any other thoughts please let me know.
@LMD001 I never experienced this before but since I am not the only person now there is a serious flaw in the sketch engine.
I really need to be able to trust that what I enter remains the same in other sketches. I will test it more
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
Hello jiang.peng,
When creating the spline, if you make sure the reference points are present and dimensioned, and you pick these, the splines are created as expected, every time, I tried this for like 30 times, so I'm guessing that it is repeatable.
If you pick arbitrary points for the spline and align the points by dimensioning and/or constraining them, the splines will deviate depending on where you have put the initial spline points.
So you end up with a different spline, even with the same dimensions.
It is as you have stated, it seems that the spline ratio is not recalculated when the spline points are realigned/moved.
So for now, probably best to use some dimensioned construction geometry to pick the spline points, and do not use random spline points to align later.
Here is a short Screencast: https://screencast.autodesk.com/main/details/717be95a-e575-41fb-822b-7e45ebf355b3
Hope is of any help.
Best regards,
Ludo
@LMD001 Very good find! I assume that is what resulted in my different arcs.
I hope this could be fixed because honestly this is a major pain in the head.
How could one even know this as an end user - this behavior makes no sense.
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
