New Stack - What does 'Live Alignment' actually do ?

[Didge]

HI,

'Live Alignment' is an option when creating a new stack - all I can find on this in the Help document is ...

Image Stacks

5. Check Live Alignment to allow the above perspective adjustment to be made non-destructively (this may affect performance depending on size and number of images to be stacked).

So I have 3 questions :-

1. What does 'Live Alignment' do exactly ?

2. Does it apply only to 'Perspective' option (if so, it should be grayed out when 'Scale, rotate and translate' is chosen) ?

3. Does using 'Live Alignment' affect performance by making it worse - or better ?

Gary

[Chris B]

1. It adds a live perspective filter to the enclosures on each pixel layer so you can tweak the alignment post-stacking if you so wish to

2. Possibly - it likely just won't work on the Scale, rotate and translate' option. I can check this. Update - Scale, rotate and translate is always live (the layers are transformed as if you have used the Move Tool

3. It will likely make it slower as it's non-destructive stacking and you will have a bunch of live filter layers which can slow things down somewhat

[Didge]

Hi Chris,

Many thanks for the feedback ...

1. OK that makes sense.

2. Can you check this ?
If so, then this option should be grayed-out when the 'Scale, rotate and translate' option is selected.

3. Actually, I would have thought non-destructive layering might actually be faster - can you confirm ?

4. (New) - can you add something to the user guide to clarify this ?

5. (New) - is there a way to make the mode selecting default to 'Scale, rotate and translate' - so I don't have to select it every time I build a stack ?

6. (New) - can we add a dialog to individually select :-
- scale
- rotate
- translate

when creating a new stack ?

I often want to translate images, but not rotate or scale them ...
as per previous posts, I want to align images of the recent lunar eclipse without rotating them,
so I can create a movie showing how the eclipse progresses and the moon rotates over time.

This would also speed up importing images because there would be less processing when rotate/scale are not wanted.

Ive already submitted this to the Fearure Request forum but havent had a response yet

[Chris B]

2. I logged an improvement to grey it out.

3. Sorry I meant that once it has finished, generally speaking more layers (especially live) will potentially slow production down as they are constantly being rendered. I've done a test with the same files and didn't notice a difference between live and destructive.

4. Yes I can ask Documentation to expand on what is there already.

5. No. We would like to see 'sticky settings' in a new version though. 

6. I can put it forward as a request, sure. Our conversation the other day lead to one of the developers interested in expanding the Stack feature.

[Didge]

Thanks Chris,

2. Great

3. My original question really related just to the creation of the stack - can you confirm whether the time taken to create a stack is significantly affected by this setting ?
I understand that processing live layers creates more processing over=head and would therefore be slower.

4. Good

5. OK - I'll look forward to seeing this win a future release.

6. That would be great - and would please many astrophotographers Im sure.

BTW - Ive been promoting Affinity Photo to Astro groups - suggesting its definitely worth downloading and giving it a try.

[Chris B]

No, I didn't notice a difference during the actual processing of the stack between the two settings.

On 8/12/2021 at 12:36 AM, Gary.JONES said:

BTW - Ive been promoting Affinity Photo to Astro groups - suggesting its definitely worth downloading and giving it a try.

Thanks! It's still a relatively new feature and I expect it to continue growing.