Heya!

I think to remember, during Jeff's Houdini 12 London's presentation, being mentioned that now there's a way to change/add attributes after the geometry has been cache and before the delayed load during render … is that true and how to archive that?
I have right now some use for it!

Thanks

Could be a new Point Instance Procedural, capable of reading bgeo from disk, which can process points' attributes with CVEX shader, afaik it can export only transformation matrix for instances. Take a look:
http://www.sidefx.com/docs/houdini12.0/nodes/shop/vm_geo_ptinstance [sidefx.com]

ahhh yeah that makes sense … although it isn't what I hoped so most likely it also ain't what I thought I'd heard …

oh well! … everything is so much faster that recaching is not yet a problem so I guess I'll try and keep double checking all my attributes.

Thanks for the hint though! I'll have a look at that.

You can add a new string attribute on your points:

string instancefile <path_to_geometry_on_disk>

You can set up everything with a single point instance object loading geometry directly from disk passed in to the point procedural and out to Mantra.

The attached example file has no reference to defgeo.bgeo (yeah it's what we ship so it's what I use…) but as defined by the instancefile attribute with an Attribute Create SOP.

The only mantra property you need on the object with the instance points is the <ptinstance> Point Instancing parameter set to “Fast point instancing”.

The viewport instance geo feature currently doesn't work with the point attribute instance and instance path. You have to supply an object reference in the added mantra property <instancepath> “Instance Object”.

Hi Jeff,

It's possible to have an example file that shows how to use point instance procedural with the cvex context?

Thanks.

alejandro
Hi Jeff,

It's possible to have an example file that shows how to use point instance procedural with the cvex context?

Thanks.

Unfortunately it seems to be broken currently (12.0.567). I've submitted a bug.

So I can just alter the xform matrices for the instances, how about attributes like pscale?

So I can not change a point attribute such as pscale on a instance object through CVEX, is that correct?

I am sorry I was confusing instancing with delayed load procedural, which I wish I could alter point attributes with CVEX.

based on this and other posts - it seems that the “whats new in houdini 12” is really very poor indeed. could sesi please provide better / more complete documentation? i think even bullet points that point to posts/threads such as this would be very useful for both users and sesi (less support/repetition of information).

Hi Jeff,

As a beginner, I am not sure about it but I think there is something wrong with your example file.

instancing_with_instancefile.hip

When I erase the link to the procedural shader in the “instance_points” render tab, the instance is still working … Can you explain it to me please ?

the first explanation coming was, the procedural shader takes the control of the instances generation. But When I try to add a cvex shader in the “cvex operator” parameter of the Point Instance Procedural … nothing changes.

My goal is to know how to instance from several bgeo sequences with Point Instance Procedural. I can make something with fast PointInstancing but I would like to use cvex to modify instanced bgeo.

thanks for your help

finally,

mixing the hip above with the example of halfdan in the “Point instance procedural” thread, i obtain something working as excepted.

I share it with you.

Now the next part :
How to override material attribute with that …