Which effector to turn of clones (grass scattering)

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  02 February 2018
Which effector to turn of clones (grass scattering)

Hello everybody!

I have a question regarding mograph grass scattering.
I'm using SHADER effector, I check visibility under "Parameter" tab and I use BOX under "Falloff" tab. 
This way I get a very neat controler that I can move around the scene and render only parts that I need to.
Problem that I'm facing is that mograph calculates ALL clones even though visibility is OFF on most of them and thus making this workflow pretty much useless. 

I know I could split polygons that I want to scatter on, but that just doesn't make the best workflow in the long run.
Is there an effector that actually turns OFF the clones, not just their visibility?

Thank you,
matej
 
  02 February 2018
Object info shows me less polygons when using VISIBILITY check in planes effector. But I'm still getting long precompiling times.
 
  02 February 2018
Yeah, that's one of the negatives with the current mograph integration. The only way around it is to create several completely separate objects on which to scatter your clones, with separate cloners on each object, turning them on/off for each render as needed. 
 
  03 March 2018
Thanks Luke.

So to continue the thread, maybe something useful still comes out of it.

The thing that bugs me when using mograph for creating realistic grass is the fact I need to constantly switch it ON/OFF when I make changes. Otherwise it takes ages to refresh.
What would help a lot would be a script or something that would keep the effector (mograph) OFF until you click on render button. This way I could make test renders way faster. 
Does such a thing already exists? If not, do you think it's doable?
 
  03 March 2018
I have not tried it, but maybe there's something you could do with the LOD object that was added in R19?  

I like the way Forester handles this sort of thing...it has a camera frustrum filter so you can have objects outside the view of the camera not exist.
 
  03 March 2018
I will try if LOD in r19 might help in anyway. I'm doubtful though because LOD optimises the polygon # and in my scenes I usually have grass elements disabled in the viewport, which means 0 polygons. I will test if it somehow affects the generation of the mograph elements in the background as well ?!
 
  03 March 2018
The LOD has a camera frustum filter as well. The setting is called "Use Camera Clip". It gets rid of all clones outside of the cameras field of view. You can also use the LOD to do what the name suggests, have lower resolution versions of your clones depending on different criteria like camera distance. The automatic polygon removal is not very helpful but you can provide the different LOD levels yourself, e.g. by using the polygon reduction generator. That will preserve the look of your model / grass blade / ... much better. 

Here is a screenshot of a grid array cloner cropped by the frustum:
 
  03 March 2018
Thanks for that Havealot!
Camera clip works great.
However. I'm having some issues with using "Distance from camera" on mograph clones. I'm not sure if I'm doing something wrong, but it just doesn't seem to affect the clones.
Any idea?
 
  03 March 2018
Here is my test.
Funny thing that happens is that in Top view I get what I'm supposed to get: Camera clip + Camera distance (look at blue dots).
BUt in the perspective view I don't see the effect.
Can anybody explain this?

Thanks,
m

PS: + one more thing I find very confusing. Camera clip stops working when I check "Render Instances" in Mograph object properties.
 
  03 March 2018
Originally Posted by fla: The thing that bugs me when using mograph for creating realistic grass is the fact I need to constantly switch it ON/OFF when I make changes. Otherwise it takes ages to refresh.
What would help a lot would be a script or something that would keep the effector (mograph) OFF until you click on render button. This way I could make test renders way faster. 
Does such a thing already exists? If not, do you think it's doable?

Someone made a plugin that did exactly that a few years ago - and I used it for a while - but I can't for the life of me remember what the name was.  I can even remember the icon, which was purplish in color, and (if I remember right) looked like two "Play" buttons overlapping each other. 
 
  03 March 2018
I've tried to find it, no luck for now. If you happen to remember, please do share
 
  03 March 2018
Another option to speed up the visibility/shader effector workflow, substitute a single polygon square face in your cloner, then collapse the cloner, connect all those squares into one mesh, and then target those squares in your grass cloner using object mode/faces. Bonus is further control by deleting unwanted faces or selecting faces and making selection sets for your cloner.
 
  03 March 2018
@Gwelchster: That means one clone per one polygon no? Does this make the viewport somehow faster?
I see the benefits of this workflow but it doesn't give you a lot of flexibility regarding the distribution and varying density of grass which is crucial for realism. Or am I mistaken?
Certainly interesting way of handling the mograph clumsiness.
 
  03 March 2018
Correct, one clone per poly face. Workflow is establish randomness with effectors first then convert to poly “object” target. This method actually culls the clones, thus not generating and hiding the clones... 
 
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