Creating a shape with a partial outline

[N. Virgo]

I'm a complete beginner. I'd like to make a shape that looks similar to the following, except that I want the vertical line on the right-hand side to look the same as the left, where there is no outline.

I will be making many scientific diagrams with many shapes of this kind, so I'm really looking for a workflow to produce them. What I want to avoid is making the filled shape and the outline curves into separate objects, because I'll be editing them a lot and don't want to have to keep them lined up manually. Additionally, the filled part should be semi-transparent. Is there a way to achieve this in Affinity Designer on the iPad?

 

[Pšenda]

Try to draw an open curve, and set it to fill with opacity.

[N. Virgo]

I don't understand what you mean. Isn't the curve I drew already an open one? It's not what I want - I don't know how to get rid of the vertical line at the right hand side.

[Paul Mudditt]

Draw it using 3 shapes is one way, the top open curve with fill, a rectangle without fill and the bottom line.

[Paul Mudditt]

Just now, Paul Mudditt said:

Draw it using 3 shapes is one way, the top open curve with fill, a rectangle without fill and the bottom line.

 

[NotMyFault]

Another option is to use a rectangular shape as mask to cut off the left/right edge.

You get a clean hard edge. If you need the round stroke edge, other methods are better suited.

 

[NotMyFault]

2 hours ago, N. Virgo said:

Additionally, the filled part should be semi-transparent. Is there a way to achieve this in Affinity Designer on the iPad?

just set fill opacity to the desired level. Stroke and fill colors and transparency can be set individually. 
There is an additional fill opacity setting in layer fx. Use that as lat resort. Layer fx often lead to rasterizing in export, and some  layer fx have unfixed bugs since ages.

[GarryP]

An alternative to the above answers could be to duplicate the original curve, break the sides away from the duplicate (with the Node Tool) and delete them, then Merge the broken curves, then only fill the lower curve and only give an outline to the upper curve – see attached image and AFDESIGN file (on Desktop but same thing can be done on iPad) which shows the same thing twice but the ‘outline curve’ at the bottom has been offset.
Note: I have deliberately made the ‘sides’ non-vertical to show the effect more.

semi-transparent-wave-with-broken-sides.afdesign

[N. Virgo]

18 hours ago, NotMyFault said:

just set fill opacity to the desired level. Stroke and fill colors and transparency can be set individually. 

How does one do that actually? When selecting the colour for the fill I don't see any opacity slider, or any option to add opacity.

[DM1]

As a ‘ complete beginner' you would benefit tremendously from watching the basic 'how to videos. The app is laid out in Personas with Tools and Studios that vary depending on the Persona selected. Once you get a feel for Personas , Studios and Tools you will be in a position to start creating. Till then you are basically stumbling around in the dark.

31 minutes ago, N. Virgo said:

When selecting the colour for the fill I don't see any opacity slider, or any option to add opacity.

The Layer 'Studio' contains the layers 'options'. When you open the Layer studio you have a selection of menus. Layer options shown in attached screen shot.

Tutorials

 

[NotMyFault]

1 hour ago, N. Virgo said:

How does one do that actually? When selecting the colour for the fill I don't see any opacity slider, or any option to add opacity.

When using the Color Studio, there is a opacity slider directly below the color sliders.