How difficult to create effects similar to those in Blade 2 movie when the skeleton were incinirating and burnning. also effects in Time Machine when the buildings were constructed so quickly to simulate time travel

Thank you

It took a lot of people a lot of time to do these effects. I worked on Blade2 on some of the Vampire ashcarbon effects, and came in after the R+D guys had set it al up. They did a great job and it was a very smooth pipeline.
The Vampires were tracked in Maya and the effects work was done in houdini.
Houdini definitely has the best tools to do this. Then the compositing guys spent a lot a time stitching it all together.
It is probably quite difficult to develop the initial production pipeline, but once that's done then things *should* go smoothly.
Sometimes there were little problems that needed to be fixed but that was pretty straightforward with Houdini.