Hi Does aanyone know whether it is possible to subtract another terrain form a procedural one. I often used this to create lakes in Vue 4. Ie. create a terrain, create a new one and invert it then subtract the 2nd from the 1st to produce a 'hole'. Thsi doesn't seem to work using procedural terrains. Is this a bug or am I missing something?

I haven't tried that in Vue 5, but I would be surprised if it worked - I would not expect it to. Procedural terrains are not as predictable as bitmap terrains as they are generated by complex mathematical models. Since they are resolution independant, it would be difficult to decide how to intersect them for boolean operations.

I'm not sure, because procedural terrains are generated and drawn differently it's likely this is something that is not possible with them (fractal versus polygonal) and in a way it makes sense, since procedural terrains are primarily generated by the function applied to them it might be too involved for it to calculate the effect of a boolean on the function.

Hmmm...Strange, because you can double-click a procedural terrain and then edit it it the same as normal terrains. I would have thought this too would have been impossible if it was a complicated mathmatical definition. Another questions is that when I try to apply one of the materials that cme with Vue to the procedural terrain it warns me that the mapping mode has to be changed. Do you need to use special materials for this typoe of terrain and if not, why is this question always asked?

You can dig on procedurals...why not dig your holes for lakes?

dlk30341: because they don't look as 'natural' as what you get with booleans. The 'dug' sides look smooth rather than bumpy.

You are right there.....

Procedural terrains use nodes to define detail, rather than polygons, when Vue askes you if you want to add nodes when applying the terrain, it's asking if you want the materials bump pattern to physically modify the terrain node mapping or if you want Vue to add more nodes to the terrain to hold the way it appears before you apply the new material. In general I've found it's best to add nodes as I usually want the terrain to hold the shape I've got and not to be modified by the material I'm applying to it. Procedural terrains are still capable of being edited in the terrain editor (as they should), but because of the node based geometry that is new to only procedural terrains it would be very involved to add booleon operation capablitiy to a procedural terrain. Agiel pretty much summed it up, lots of mathematics behind the scenes. One other thing, you can still do it the way you did in Vue 4, but only with the standard terrains (I wasn't clear from your question if you thought Procedural terrains were the only ones available any more). Hope this all helps.

Thanks for the info everyone - thats cleared this up a bit. Cheers