Using auto paint for auto erase Topic is solved

[MelMo]

Hi TV paint users,

for a while I've been struggling with the following, maybe somebody can help. When using auto paint, or drawing with CTRL on, I can make a line move along a path. When the path comes at the end of the instance, I have a fully complete form. Let's keep it simple and say I've been drawing a line from left to right, at the end of the instance I have a line visible moving from left to right. So far so good.

Let's say my instance is 24 frames. What I'd like to do is that the line runs along a path, but from frame 10 until frame 25 the left part of the line (let's call it the tale) starts to become erased. So in this new situation, the line, when coming to frame 25 is fully erased (well actually probably I will make the instance 30 fames, so when the line stops on the right, it takes another 5 frames to dissapear fully). Line appears moving from left to right from frame 1 - 25. Line dissapears starting from the left from frame 10 - 30.

I can do this manually, by erasing the line frame by frame starting on frame 10, but this obviously doesn't take advantage of the automated auto-paint - recording tool.

Is there a way to set the auto-paint function so that the line is also automatically erased after it has started to appear?
Thank you in advance for your time and efforts to help me out!
Best wishes,

Melvin Moti

[MelMo]

Sorry I forgot to write my details:

OSX 10.11.6 El Capitan. 8GB RAM Macbook pro retina from 2012.
TV paint PRO 11.
Wacom Intuous Pro

Thank you very much in advance for advising me how to 'auto-erase' a line made with 'auto-paint'.
Looking forward to your suggestions!

Best regards, Melvin

[slowtiger]

Maybe I don't understand, but what about just copy&paste the last frames and reverse them?

[MelMo]

Hello Slow Tiger,

sorry my description was too unclear. I attached a project showing the effect I want to achieve. This is done manually: with auto paint I made a line and then I MANUALLY erased the beginning of the line again. This way, as the line progresses, the start of the line is erased.

I would like to achieve this without manually erasing the line, and somehow use the "auto paint" function (or other functions) to erase the line.

When I copy&paste the last frames and reverse them, the line will be erased from the end of the line back to the beginning (reversing the direction of the drawing). However, as you see in the project, I would like to erase the line from where it started towards the direction, following the direction of the drawing.

Anyway, more unclear descriptions, I'm doing my best but please open the project and it will all make sense.
This is so simple that there must be a simple solution, only I can't find it!

Thank you for your time and helping me out!

[slowtiger]

Ah! I think I understand now. You want a line which grows up to a certain length, then keeps that length while continues to grow, like a crawling snake.

In TVP11 it should work - in theory. You can invert all keys of the FX (caution - don't select all first - just inverse! (this is a bit confusing)), and I would expect that autopaint works in reverse now. In praxi, however, I got no result!

I'm at loss here.

There's another hack, however: let autopaint draw a black line. Create a new layer on top, increase your brush size by 2 px, select white colour, and re-apply FX. Now shift this white layer to the right, you'll see the black line starting and, after a while, being covered by th white line. Merge the two layers and apply Scan cleaner. You now have a black line behaving as you want, and can colour it to your liking. The only disadvantage would be that the end of that moving line will have a dove tail instead being rounded, this needs to be corrected manually.

[MelMo]

Hi Slow Tiger,

thank you, and exactly, I'm looking for something like a snake; keeping the methaphor of 'head' and 'tale' I want a line where the tale eats the head. Thank you for your hack.

It's so simple, and I was at a loss too, but I was so embarrased about posting something so, so simple, that I have been breaking my head on this for about 2 weeks. I'm glad the hack is not so straight forward.

I think this will definately work, I understand the system now, and especially understand there is no setting within auto-paint to make this effect happen.
Thank you!
Best regards,

Melvin

[melanie]

Hello MelMo and Slowtiger,

You can actually use Auto Paint to get this result.
In the "Stroke" parameter choose "Size", it will give your stroke the size you want. In other words, a head and a tail.

I made a video that shows the process:

autopaint.mp4

(13.94 MiB) Downloaded 1194 times

[slowtiger]

Ah! That's great. I assume the numbers in that field correspond to the number of keys?

May I suggest to rename it to "length", because Size is used for Brush size everywhere else.

Now if anyone could also explain why the inverting of keys didn't work.

[Elodie]

May I suggest to rename it to "length", because Size is used for Brush size everywhere else.

Indeed... But I'm afraid it's going to be a little complex to change on my side because the parameter "size" is used at different places in the FX stack and if I change it, all effects will be affected.

>to do list.

[MelMo]

A little late from my side, as I didn't see this reply earlier. I was following Slow Tiger's directions, but this video is perfect and serves my needs perfectly! Thank you Elodie and Melanie!