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Showing posts from May, 2009

Cloth wind shadowing

More cloth!

Got some wind shadowing working using the same technique as the wind resistance thing, just with a ray SOP to block the wind.

Currently the wind gets blocked by any other objects in the dopnet. Might add self shadowing next!



This is with wind resistance from earlier, just adds some damping.



hipnc is here.

Cloth and wind resistance

Normally a cloth like this:



would just fall and retain this exact shape... I put together a little force using the field force DOP and a little sopnet to get a basic simulation of wind resistance as it falls.

The force is applied along the normal, opposing the velocity. It is also scaled by velocity.

Here is an example:



Blue is the point normal, green is the velocity and red is the force to be applied.

This is far from correct but it works alright in practice.

This cloth is 2m x 1m and low density (less than a kg total I think)



hipnc file is here!

PBR fun

Just playing around with PBR, also was reading about linear colour space so I was also experimenting with doing a sRGB > linear coversion to the textures -- before .rat creation as the mipping is wrong in sRGB. A 2.2 gamma is applied when viewing the render in mplay and also applied when saving a .jpg. I understand it all a little bit better now, that workflow seems to work alright.

Just used the Galileo's Tomb HDRI from http://www.debevec.org/ with no other lights.

hipnc file is here

Growing Objects

I saw this post over at odforce and have been playing with growing objects in a dynamic way ...



It is basically just points scattered in the volume of an object, then a SOP solver is used to increase a points pscale if it is colliding with another point. Metaballs are copied onto the points, converted to polys, then cookied with the original geo (not in the video above though...)

This is the source geo and with the scattered points:




Some attributes are added for the sim:



The pscale attribute is set to 0 except for one which is set to maxSize to start the sim going. Roughness starts at 1 and decays when a point has stopped growing, this later is fed into the shader to increase the cone angle on the reflections and refractions...

These points get loaded into a DOP network and then into this SOP solver:



The pointCloudSop is a little VEX script that tests for collisions between points:

#pragma hint filename oppath
#pragma hint pscale hidden
#pragma hint maxSize hidden
sop
pointCloudSop(string fil…