handy hdt stuff

Link: https://www.loverslab.com/topic/25491-hdthavokmodifier-just-for-fun-jff-v4/page/3/



BBP / JFF Guide



If you want fast solutions without too much optimizing (unlike me for 5 days straight). The most import values are marked in blue.

They give instant results and are most responsive for bounce. But keep in mind to get something really awesome out of this takes lot of time.





1.) Basic understandings



1.1) Understanding the Havoc object

From what i experienced it's like a spring or a bumper that causes a strong repulsive force in one linear direction.

Movements are being created from animations in the first place but the physics cause strong repelling in one direction.

Don't get it wrong, changing the parameters can affect on all axes/movements but the repelling force is focused so to say. A matter that can't be changed

By default the "repelling or strong axis" is the linear Z-axis (up/down).



1.2) Understanding the axes

- the linear axes for linear (straight line) movements (Z=up/down, X=left/right, Y=in/out)

- the angular axes for rotational movements (Z=left/right rotation, X=up/down rotation, Y=clockwise/counterclockwise rotation)



2.) Adjusting Parameters (Rigid body)



2.1) Rigid Boy > Generic Properties > Name / Motiontype / Friction / Restitution

Friction and Restitution don't seem to have any noticeable influence (maybe doesn't apply to a sphere), Name and Motion type must not be changed.



2.2) Rigid Boy > Advanced Properties > Linear Damping

This parameter indicates how hard/soft the dampingis are. It affects the bouncing duration. This is the master bounce factor.

Increase this value to decrease the bouncing duration, or decrease it to increase duration.

Seems to apply to all linear axes but like mentioned the biggest result you will notice for the "strong axis"



2.3) Rigid Boy > Advanced Properties > Angular Damping

Same as linear damping but for angular axes. Here i'm not sure if there is a "strong angular axis", i doubt it.

I recommend setting this between 0 - 0.2 otherwise the breasts might stuck on their reversing points due to the lacking rotational force by default.



2.4) Rigid Boy > Advanced Properties > Gravity

Maybe obsolete or only influences certain circumstances, i can't figure out what or if this changes anything at all.



2.5) Rigid Boy > Advanced Properties > Timefactor

Overall processing speed... for the case you want slowmo boobs



2.6) Rigid Boy > Mass Properties > Mass(kg)

A bit tricky. Imagine filling a balloon with either water or air

more water means: more "flappy" behavior, longer bounce duration, slower speed movement

more air means: the opposite effects

If you want a fast solution maybe don't change this since it takes time to optimize and influences other parameters greatly.

additional info: if you increase the weight you have most likely to adjust linear ranges in Constraints (see 3.3) as well because if the range is too small you might suddenly loose

all repelling force in an instant. It's like smashing your breasts on the table before they reach the bumper



2.7) Rigid Boy > Mass Properties > Center of Mass

Changes weight position (imagine a unbalanced weighted ball) All movements are being affected by that.

To not go too much into detail, increasing Y-parameter causes stronger swing motions (talking about real pendulum swings not just linear stretching)

But be warned, if you want perfect "swing doors" this can get quite a very difficult and time-consuming task and maybe not turns out in what you expected.

If you mess with this values will often have the result that the breast just stuck at the weight spot.



2.8) Rigid Boy > Mass Properties > Inertia Tensor

.... this is beyond me. If you are curious google or wiki for "moment of inertia". This is rather something for an absolute pro.



2.9) Rigid Boy > Mass Properties > Collision

Select the Body Part(s) that the selected bone should collide with if you use a collision body. Eventually change the radius (under shape) for clipping issues.

No idea about the numbers but i think they represent bone numbers from the entrie skeleton.





3.) Adjusting Parameters (Constraints)



3.1) Constrains > Joints

Here you can move the anchor (the 0-point) for the axes. Values apply to linear and angular axes.

Pivot A and Pivot B seem to have a different behavior while B seems to be smoother. So if you change anything here, i recommend Pivot B.

You can use it to fix small morphing issues. This does also influence the overall behavior but i think it is rather meant for troubleshooting. Examples:

- flat breasts, spiky or twisting nipples: change the Y-axis.

- hanging or too much lifted breasts: change Z-Axis



3.2) Constrains > Linear Limits > Linear Basis

This is vector related stuff and would therefore be too much to explain here. To put it simple you can change direction of the main repelling force.

For example setting Pitch(Y) to something around 1.0 causes the repelling force towards the X-axis. So the boobs swing strongly to left/right but not so much up/down anymore.



3.3) Constrains > Linear Limits > Linear Limits

For a change something that can be explained easy. Set the min/max stretching ranges here.

Values have 0-reference so a bigger value (away from zero) means a bigger range in either positive or negative direction.



3.4) Constrains > Linear Limits > Friction / Linear Motor

uknown



3.6) Constrains > Angular Limits > Angular Basis A / B

Vector related again. I'm not entirely sure since this is rotational axis, therefore i guess it just creates a angular offset more or less and Basis A and B seem to negate each other. This requires a real pro again.



3.7) Constrains > Angular Limits > Angular Limits

same as linear limits just applies to angular axes.

additional info: if you see that rather your nipples spin but not the rest try to move joint in -Y direction because it means the bone and so the anchor is too far in the frontal part

of the breast