Pressure Advance Pattern Too Small #856

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MrUnknownDE · 2026-04-05T16:33:17+02:00

MrUnknownDE commented

2026-04-05 16:33:17 +02:00

Originally created by @Fuzzyl0g1x on 2/7/2026

Is there an existing issue for this feature request?

I have searched the existing issues

Over the past 10 months, I've been concerned about why my pressure advance test results at high speed show a non-linear trend compared to medium and low speeds, and I just realized why: the damn pressure advance pattern is too small to support testing above ~235 mm/sec at 2k accel or 375 mm/sec at 5k.

It wasn't until the "actual flow" view came out that I realized what was happening and did some math to confirm the results:

To fix this problem, the size of the pressure advance pattern test should be increased, selectable, or dynamically scaled to support the speed/acceleration requested by the user.

Presently, the pressure advance pattern consists of two 45 degree lines in a 20x20mm grid (40x20mm pattern). Therefore, each straight line measures 20*sqrt(2) = 28.28mm long. The maximum speed achievable on a 28mm straight line is:

2k accel, 9-27 jerk = 236-238 mm/sec
5k accel, 9-27 jerk = 374-375 mm/sec

To support testing at speeds up to 500 mm/sec at 5k, each line in the pattern test would have to be 50mm long (70x35mm grid). At 2k, each line would need to be a whopping 125mm long, which is probably untenable, but if we increased the PA test lines to 50mm length, everyone would be able to test up to 315 mm/sec at 2k, which is a big improvement.

Which printers will be beneficial to this feature?

All

Describe the solution you'd like

The PA pattern should be increased in size to support higher speed testing.

Solutions arranged from easiest to hardest are as follows:

Increase the size of the PA pattern test from 20x20mm grid (40x20 pattern) to 35x35mm grid (70x35 pattern).
Give the user a set of radio button options for grid patterns measuring 20x20 (< 235/375 at 2k/5k), 35x35 (< 315/500), 70x70 (< 375/600), and 100x100 (< 450/700).
Dynamically scale the size of the PA pattern to accommodate the speed/accel parameters the user wishes to test.

My recommendation is Option 2, since the third option seems like a nightmare to implement for all nozzles and user inputs.

Describe alternatives you've considered

No response

Additional context

No response

*Originally created by @Fuzzyl0g1x on 2/7/2026* ### Is there an existing issue for this feature request? - [x] I have searched the existing issues ### Is your feature request related to a problem? Over the past 10 months, I've been concerned about why my pressure advance test results at high speed show a non-linear trend compared to medium and low speeds, and I just realized why: the damn pressure advance pattern is too small to support testing above ~235 mm/sec at 2k accel or 375 mm/sec at 5k. It wasn't until the "actual flow" view came out that I realized what was happening and did some math to confirm the results: <img width="1718" height="924" alt="Image" src="https://github.com/user-attachments/assets/98547960-60be-4b8e-a861-a1aa87207541" /> <img width="1712" height="951" alt="Image" src="https://github.com/user-attachments/assets/ec228e74-f7a7-42c3-b4a7-7040b2a1deaa" /> To fix this problem, the size of the pressure advance pattern test should be increased, selectable, or dynamically scaled to support the speed/acceleration requested by the user. Presently, the pressure advance pattern consists of two 45 degree lines in a 20x20mm grid (40x20mm pattern). Therefore, each straight line measures 20*sqrt(2) = 28.28mm long. The maximum speed achievable on a 28mm straight line is: - 2k accel, 9-27 jerk = 236-238 mm/sec - 5k accel, 9-27 jerk = 374-375 mm/sec To support testing at speeds up to 500 mm/sec at 5k, each line in the pattern test would have to be 50mm long (70x35mm grid). At 2k, each line would need to be a whopping 125mm long, which is probably untenable, but if we increased the PA test lines to 50mm length, everyone would be able to test up to 315 mm/sec at 2k, which is a big improvement. ### Which printers will be beneficial to this feature? All ### Describe the solution you'd like The PA pattern should be increased in size to support higher speed testing. Solutions arranged from easiest to hardest are as follows: 1. Increase the size of the PA pattern test from 20x20mm grid (40x20 pattern) to 35x35mm grid (70x35 pattern). 2. Give the user a set of radio button options for grid patterns measuring 20x20 (< 235/375 at 2k/5k), 35x35 (< 315/500), 70x70 (< 375/600), and 100x100 (< 450/700). 3. Dynamically scale the size of the PA pattern to accommodate the speed/accel parameters the user wishes to test. My recommendation is Option 2, since the third option seems like a nightmare to implement for all nozzles and user inputs. ### Describe alternatives you've considered _No response_ ### Additional context _No response_

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Reference: github/OrcaSlicer#856