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VRay Fur - editing gravity axis


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I'm having a lot of fun with the vray fur and displacement tools but I have question specifically about Fur Gravity.

I can't seem to work out how to change the gravity direction and it always points along the Y.

I have tried using the FormZ edit axis tool to rotate the object axis and also just tried rotating the objects etc.

Same regardless of when you apply the fur - before object or axis rotation or after.

Nothing seems to work to alter the direction of the gravity pull.


Am i missing something really obvious here?


This is a major issue if the axis cannot be changed or moved. (eg all grass will be pointing sideways...)







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  • 1 month later...

Just thought i'd say that i am enjoying immensely exploring the VRay fur functions in the plugin.

The axis options seem pretty good so far for manipulating the output.

And there is good range of controls to create interesting variations on surfaces not just standard hair and grass...


This test is a combination of surfaces to create organic cellular structures etc.



I'd still like to see some volumetric cloud and fog controls though...

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Had no luck with fur! whenever I wanted to edit the gravity vector, it seemed that it only accepted 0 or

106087766069853106366965505980987196957894973210433529048207319258357466079500671557600018432  :o

And fur never shows!!!!

Could someone post a .fmz file to try it out?





Mac OSX 10.9.5 FormZ 8.6 build 10025 VRay evaluation




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Hi - here's a quick guide... that might help get it started...


create a sphere of about 2m diameter ... roughly... just not too big or too small.

Add a highly visible texture like a VRay green grass ground material to it.


Set the gravity to 0

leave the gravity vectors all at 0

make the base length higher than 50

add the fur by selecting the fur tool and then apply it to the sphere.

do a test render and it should look something like this


keep changing the length higher or lower till you can see a significant amount of fur length sticking out in all directions.

If you cant see any fur at base gravity 0 then it's probably one of the other settings that is going wrong


now change the fur settings to gravity 5

and change the gravity vector for Y to 1

add the fur by selecting the fur tool and then apply it to the sphere.

do a test render and it should look something like this



basically the gravity has to be set above 0 or below 0 to make the fur effect work otherwise it basically just has no gravity acting on it.

The vector defines the direction in increments between 0 to 1 or minus 1.

If in doubt just set it to -1 or 1 as you can alter the effects with the negative and positive gravity as well to get the same effect of movement as setting it to plus/minus. ie. if you set it to -1 Y then setting the base gravity to a negative number will kind of override it in part and point it in the opposite direction.


so to summarise this...

So you can combine the vectors to create a 3D direction - say -  .2 along the -Y axis and .5 along the left axis -X

The base gravity is the overall strength or pull and that can also be set to be either positive or negative or 0 where there is no pull at all and the fur just points in random directions out from the object based on collision between the individual fur objects.

You can also alter the Gravity variation which defines how much each hair is randomly affected by the gravity and direction pulls.

This is most evident at the point where the fur is attached to the object.


You can then also alter the fur to get extensive other options in its formation and clustering.

And if you try the variations for distribution you can alter the density etc.


Once you have applied the fur you can edit the settings for individual objects without having to reapply it via the fur tool by right clicking on the object and editing the fur attributes directly in the object settings.



hope this helps and you get some fur happening...







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BTW - i have had a few occasions where i have had to use the reverse normals tool on objects that have a strange geometry form and the fur did not appear because it was all inside the object. Reversing the normals will usually correct this.

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There is a lot of fun to be had playing with this that will suck up time like a blackhole...


If you initially set the base length of fur very long it makes the minor changes to the variables much more obvious and easier to test out.


Some of the most interesting variables to play with are the distribution - try setting it to something like 0.002 or even lower lower and see what happens.

Also try setting the base size to a large number like 15 or more and the base length like about 20 and watch the cells interact.

It's great for imitating organic structures and things like stone paths and foam surfaces when you do this and play with the taper.

this has 0 gravity base.



Also I have found that the origin surface shape makes for a lot of variation - so for example try a flat disc, a torus, a cube. a hemisphere and a twisted mesh all with the same settings and see what happens... applying it to various subdivision surfaces are also very interesting...


Building fabrics with a bit of fur surfacing can be fast and sometimes more effective than just a single material fabric surface - but in combination with the displacement tool you can get some very nice effects. It can just give the objects a bit of a visual 'lift' that helps suspend visual belief...

Here is an example throw rug that i threw earlier... a fabric material with furry fibres added for extra texture...


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Hi Nano,


Thanks for the detailed information! The blob structure is pretty ingenious!

Without your help, I still get stuck in trying out fur functionality!

With a little tinkering, things like a carpet and gras and some special surfaces renders seemed now achievable in FormZ!

I think I had to buy Vray! Pretty good results in no time(compared to Maxwell)!





BTW, funny that I´m a newbie, since I use FormZ since 2.9...



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Yeah some of these features are things that really fill some big gaps that have been there in formz for illustration use.

There are so many materials that can be enhanced using these tools if carefully applied.


There have been many times that i have had to place very accurate and carefully modelled objects with very ordinary rendered surfaces into what i would consider very crap looking surroundings because i ran out of time and/or could not create or apply suitable materials, camera and lighting effects.

Even if not applied to the core detailed models for a project this plugins extra tools still allow for a better visualisation context.


I also have been using Formz from the early times and I think this is actually a significant improvement - especially with the speed to quality of imaging results ratio.

I still see Formz as a solid and reliable modelling tool that does most of what i want to do quickly and efficiently and this just adds another layer of interest and reliability to its use for me.

And there is a huge history of use of VRay out there to refer to for ideas given the range of other modelling software and platforms that also use VRay. It's just a matter of working out how it works specifically in this new software context and getting the most out of it.

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