Jump to content
tristanbay

Geometry tools slightly distort shapes as well as slicing them

Recommended Posts

The algorithms for some of the geometry tools seem to be slightly off when calculating where the finishing shapes should be. In the video, I placed a blue circle under the red one to show that the combined shapes to be divided before I do it don't match the combined shapes after I hit "Divide."

Share this post


Link to post
Share on other sites

Hi @tristanbay,

Sorry for the delayed reply. 

This is not a bug. Those are not perfect geometric circles, but a curve with 4 bezier nodes. When dividing, it cannot be 100% accurate - You are zoomed in to 75000%, so this is expected.

Thanks,

Gabe. 

Share this post


Link to post
Share on other sites
3 hours ago, GabrielM said:

This is not a bug. Those are not perfect geometric circles, but a curve with 4 bezier nodes.

As I understand it, the developers hope to add ellipses/circles defined by their actual geometry (radii, I suppose) at some point, but there is no ETA for that.


Affinity Photo 1.7.2, Affinity Designer 1.7.2, Affinity Publisher 1.7.2; macOS High Sierra 10.13.6 iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM
Affinity Photo 1.7.2.153 & Affinity Designer 1.7.2.6 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iOS 12.3.1

Share this post


Link to post
Share on other sites
7 hours ago, GabrielM said:

Hi @tristanbay,

Sorry for the delayed reply. 

This is not a bug. Those are not perfect geometric circles, but a curve with 4 bezier nodes. When dividing, it cannot be 100% accurate - You are zoomed in to 75000%, so this is expected.

Thanks,

Gabe. 

This doesn't make complete sense, though, because a regular circle looks the exact same in AD as a circle that has just been converted to curves. If a circle can be perfectly translated to curves in AD, then why can't it do a shape division correctly? Does it make it that much more complex to calculate so it just approximates it?

Btw, Inkscape seems to do the exact same thing except it's even less accurate (it's clearly visible at less than 10000% zoom I believe)

Share this post


Link to post
Share on other sites
1 hour ago, tristanbay said:

You are zoomed in to 75000%

1 hour ago, tristanbay said:

a regular circle looks the exact same

"This doesn't make complete sense" to talk about "look" concerning geometry + precision @ 75.000% zoom.


macOS 10.12.6,  Macbook Pro 15" + Eizo 24"

Share this post


Link to post
Share on other sites
1 hour ago, tristanbay said:

Btw, Inkscape seems to do the exact same thing except it's even less accurate (it's clearly visible at less than 10000% zoom I believe)

Inkscape has adjustable Numeric precision accessible.

Share this post


Link to post
Share on other sites
1 hour ago, tristanbay said:

This doesn't make complete sense, though, because a regular circle looks the exact same in AD as a circle that has just been converted to curves.

But it is not a perfect circle to begin with, just a close approximation of one using Bezier curves. See for example is-it-possible-to-generate-a-circle-with-a-bezier-curve for much more about the math.


Affinity Photo 1.7.2, Affinity Designer 1.7.2, Affinity Publisher 1.7.2; macOS High Sierra 10.13.6 iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM
Affinity Photo 1.7.2.153 & Affinity Designer 1.7.2.6 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iOS 12.3.1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×