18 replies to this topic

[Gravy]

Hi all, I've been away from the VP scene for 10 years but just getting back into it and it is amazing to see the advances, well done to everyone involved.

 

Just thought I'd mention a little physics oddity I've noticed on some tables with regards to captive or supposedly stationary balls that just seem to keep spinning in place. This is really only noticeable if you use a decal/scratch texture on a ball to show it's rotation OR if you press F11 and have a look at the dots on the ball and see that it is spinning in place. This also happens when the ball drops into the plunger lane at least on some tables.

For an example of what I'm seeing, try the Last action hero table by Javier or the mod of the same table by Bigus and have a look at the captive ball at the right of the table when pressing F11. The ball appears to be vibrating slightly and spinning in place. Nudging the table will cause the captive ball to almost stop spinning but then a few moments later it will start to spin faster again.

I tried changing the table friction all the way up to 1 but it has no effect on the spinning.

I did notice that when the table is nudged the captive ball seems to pop up a bit as expected, then drop back into place whilst spinning very slowly, however a moment later it seems to drop another mm or two and at that point is when it starts spinning faster again, almost as if it drops very slightly below the surface of the table (or maybe slightly floats above the surface) and is therefore not subjected to table surface friction?

Anyone else noticed this or is there an existing thread?

[wiesshund]

Have only noticed it if the ball is forced into a position where it can not properly rest, or if you got 0 friction.

strangely set elasticity etc or sometimes just the shape of what the ball is resting on.

Like my centering block at the plunger is a V
so ball kind of works against 2 sides, and it would spin with a logo'd ball.
so i set it to be non elastic, and high friction, and it stopped, now it drops into the V settles and does not continue to spin.

I think it is mostly a visual effect?
Seems to have no influence on the actual motion physics.

Your popping and dropping ball though, that almost sounds like it is having a legit physics fight with some surface?

[Gravy]

Good to know its not just me. I've seen that plunger lane issue you mentioned a few times and usually it happens when the ball is not quite in the V correctly and resting against a side wall of the plunger lane I think.  I had a play with adjusting the friction and elasticity on the pins and rubbers that hold the captive ball on last action hero but it didnt seem to fix the issue. The captive ball on the left side of this table also spins in place, however much more slowly compared to the one on the right.

I think I'll mention the issue on the thread for Bigus' mod of Last action hero and see if they may be able to figure out what the problem is.

[gtxjoe]

VPX introduced ball spin into the physics 6-7 years ago. Balls in rest spinning is one of the side effects that we live with. You might be able to tweak the objects it is resting against to stop it. Change shape or change a point from smooth to no smooth etc

[bigus1]

The ball will sit still if it is resting against straight surfaces. On LAH, the rubbers are very circular. If you make them D shape, with the flat sides forming a V to cradle the ball, the motion will cease. The control points at either end of the straight edge should have smoothing off. I deleted 3 control points on each rubber and moved the rubbers together slightly to stop the ball escaping. Dead still

[Gravy]

Thanks for the added explanation gtxjoe and also to Bigus for a possible fix to that particular table, I guess the D shape will be not so noticable visually as we will be mostly viewing the rubbers from the curved side if I understand your explanation/fix correctly.

[bigus1]

The collidable rubbers aren't visible on LAH, and it's definitely the fix for any table. Add a couple of invisible walls if you prefer not to alter visible stuff on tables.

[Gravy]

The collidable rubbers aren't visible on LAH, and it's definitely the fix for any table. Add a couple of invisible walls if you prefer not to alter visible stuff on tables.

Does seem to have done the trick when I made your suggested change to the rubbers. There is now just a tiny amount of very slow ball rotation now and not really noticeable with decals, can only really see it with F11 ball dots.

It's funny how the ball does tend to wriggle out of its captive rubbers eventually if you dont move them together closer.

Are most other table designers generally aware of this fix already?

Edited by Gravy, 16 November 2020 - 02:56 AM.

[jpsalas]

 

The collidable rubbers aren't visible on LAH, and it's definitely the fix for any table. Add a couple of invisible walls if you prefer not to alter visible stuff on tables.

Does seem to have done the trick when I made your suggested change to the rubbers. There is now just a tiny amount of very slow ball rotation now and not really noticeable with decals, can only really see it with F11 ball dots.

It's funny how the ball does tend to wriggle out of its captive rubbers eventually if you dont move them together closer.

Are most other table designers generally aware of this fix already?

 

 

That's why I always use a cvpmCaptiveBall. This way there are no extra collisions that VP needs to handle, no ball movement at all.

[Gravy]

Thanks JP, I did a little reading and it's interesting how the cvpmCaptiveBall method works. I guess this also helps cut down on processing power very slightly too but every little bit helps on older PCs.

[Ben Logan]

If the spinning ball drives you nuts, maybe remove the decal? Haven’t tried it myself, but I’m thinking it will be unnoticeable if scratches are disabled (?)

Edited by Ben Logan, 16 November 2020 - 08:38 PM.

[wiesshund]

If the spinning ball drives you nuts, maybe remove the decal? Haven’t tried it myself, but I’m thinking it will be unnoticeable if scratches are disabled (?)

Depends on the table and ball graphics used

on heavy metal, if you do that, you may as well just copy in JP's nice chrome ball, as the swirling loc'nar orb of a ball kinda depends
on the ball being able to spin some to get the effect that it is moving inside.

Other tables have themed balls of different sorts that would lose all their magic if you did that

[Gravy]

If the spinning ball drives you nuts, maybe remove the decal? Haven’t tried it myself, but I’m thinking it will be unnoticeable if scratches are disabled (?)

Yes that would mostly fix the visual issue although the ball would still tend to visibly vibrate slightly. However my personal feeling is that the ball looks somewhat flat and dead without a scratch texture to indicate that it is actually spinning. Thinking back over ten years now I remember suggesting to Chris Leathley to implement a  scratch texture feature into Future Pinball which he ended up adding, not sure when it made it's way into VP or if VP was already ahead on this front? It's always been something which I thought added a lot of life to the game.

[jpsalas]

Thanks JP, I did a little reading and it's interesting how the cvpmCaptiveBall method works. I guess this also helps cut down on processing power very slightly too but every little bit helps on older PCs.

 

Yes, with the older computers, adding 2 captive balls could bring the table speed to a crawl due to too many hit events. The new computers will handle the extra hits quite well, but if you also add some fast timers, then you may wonder why the table stutters and the fps are not like the others.

 

If the spinning ball drives you nuts, maybe remove the decal? Haven’t tried it myself, but I’m thinking it will be unnoticeable if scratches are disabled (?)

Yes that would mostly fix the visual issue although the ball would still tend to visibly vibrate slightly. However my personal feeling is that the ball looks somewhat flat and dead without a scratch texture to indicate that it is actually spinning. Thinking back over ten years now I remember suggesting to Chris Leathley to implement a  scratch texture feature into Future Pinball which he ended up adding, not sure when it made it's way into VP or if VP was already ahead on this front? It's always been something which I thought added a lot of life to the game.

 

 

VP has always had a spinning decal that you could add. Actually the older VP versions, VP9 and backwards, had 2 decals you could use, a front decal and a back decal.

[samballuga2]

Something very similar happened to me.
The solution, a bit banana but effective, was to set up a timer that every X time verifies if the ball has undergone an X, Y, Z movement greater than, whatever we want.

If so, we can give it a push, modify X, Y, X, modify speed X, Y, X ...

In general, the more sophisticated a software is, the more difficult it is to shed light on errors and even more difficult to fix them.

VPX with 7 patches and it keeps giving problems.

The initial charm has been lost.

It's just an opinion.

Cheers

[jpsalas]

I agree VPX is not perfect, well, I have never seen a perfect program Even the latest photoshop is not perfect, it is slow as hell

 

All these reminds me of Bruce Lee teaching his pupil in Enter the Dragon (yeah, I know, I was a Bruce Lee fan 45 years ago ), and he told him "it is like a finger pointing away to the moon... don't concentrate on the finger or you will miss all that heavenly glory".

 

 

If you only concentrate on the small errors, you will never get anything done You know, improvise, adapt, overcome And I can add, use the experience of the older ones Use the cvpmCaptiveBall! It works

[samballuga2]

Many professional programmers still program in VB6 (from the year of the chestnut). Powerful, simple, exportable. .NET appeared with its 50,000 variants, updates, patches, etc. and it has not caught on.

I have not found anything yet that cannot be developed in VP9. That if, investing many hours researching.

They are still very personal opinions.

Be water my friend !!!!!

[Redwings13]

Thanks jp. Now I’m gonna watch “Way of the dragon” tonight

[Gravy]

 

VP has always had a spinning decal that you could add. Actually the older VP versions, VP9 and backwards, had 2 decals you could use, a front decal and a back decal.

 

Yeah, I seem to remember that functionality years ago although if I remember correctly it couldn't originally really be used as an effective scratch texture as the decals would not cover both hemispheres of the ball and the decals appeared quite small? It did give an indication that the ball was actually moving though. I think I may have first seen scratch texturing on one of the early Zen Pinball games and thought it added a huge amount of realism to the ball which prompted my suggestion to Chris as a feature for FP.

By the way, I love how this thread has segued to Bruce Lee movies....  haha.