How to draw curves with specific pitch points


#1

I am trying to draw a sleeve pattern with pitch points specified in the instructions like this.

For this type of curves, is it possible to draw one arc with an additional point in the centre to control the curves? I ended up drawing two curves instead but I find that the curve is not “natural” since it is manually adjusted.

If it is possible to draw this curve accurately using the proper curve tool, please tell me which one I should be using.

I also noticed there is an option dialog that pops up when drawing curves. I tried playing with the settings but could not get the curve to meet the pitch points properly without using the handles. What do the settings Length ratio, angle and coefficient of curvature mean?

Thank you so much for helping this newbie :blush:


#2

Valentina support two ways describing such curves:

  • Instead of Simple curve you should use Curved path. Simple curve connects only two points. In contrast, Curved path connects two and more points. And adjust them “naturaly”. So no need to worry about segment, they always will be curved.
  • Simple curve support formulas that allow you manually imitate “natural” behavior. Each curve’s foot should have opposite angle to their neighbour’s foot. But this is part of new upcoming version 0.5.0.

This comes from nature of curves we use. Our curves based on Cubic Bezier curves.

For example:

So, length is distance from P0 to P1 and P3 to P2. The same story about angle, from P0 to P1 and P3 to P2. The coefficient of curvature change the length for whole curve.

But be aware, we do not describe length as length ratio anymore. We moved to direct value in pattern units in upcoming version 0.5.0.


#3

Thank you dismine, I managed to use curved path and the result was much better. I could not find out how to end the path at first, kept trying to use Esc key. Turned out I should have hit enter instead. :blush:


#4

Valentina shows you instructions in the status bar.


#5

:blush: I just discovered that! plus how I can change the size easily by just using the drop down. Still discovering the software and learned alot today. Thanks so much!


#6

Offtopic. How did you find about Valentian?