Special material transparent to view but opaque to sun??

[Anonymous]

It would be brilliant to have a special material that is totally transparent to view but will still cast shadows like a solid material.
With this, the obscuring structure between viewer and area of attention could be changed to the magic material so that internal observations of sun access could be made.
An example would be to generate a vertical, parallel projection, Sun Study, of a selected unit, showing the totality of the unit in a single Sun Study, in a multiple housing project.
Is it possible to have such a material?
Is it possible, say in Lightworks, to do this already?

David
ArchiCAD 11

[Anonymous]

It's not possible directly in ArchiCad or else I have missed something. I think there is a request of this feature somewhere in this forum.

[stefan]

This is possible in most visualization programs (3ds max, VIZ, Cinema4D etc...), but not in ArchiCAD.

[Palawat]

How about this?

In LW, set your material's Colour Class to Plain > pure black and set the Transparency Class to Plain > pure black also.

[Anonymous]

Hi David,

I'm not a LW expert like Dwight... But If I well remember, he talked sometime ago about a "Shadow Catcher" material that could do what you want. Hope it helps.

Here is the link.

[Dwight]

There appears to be no solution for this issue - and shadowcatcher doesn't work that way, either.

[Anonymous]

Palawat wrote:
How about this?

In LW, set your material's Colour Class to Plain > pure black and set the Transparency Class to Plain > pure black also.

This works!!
This gives me the result I want.

I do need work on it some, to be familiar enough to get a handle on how best to make Sun Studies with this, and view sun penetration of a specific dwelling unit, in parallel perspective from above.

Thanks Palawat, and everyone.

Maybe I can impress Dwight with this and get it in a 'LightWorks in ArchiCAD' update!

Sun access and shading for dwellings seems to be a bigger compliance issue in Australia than in other countries.

David

[Dwight]

I am familiar with the Transparency Class Shader "plain."

However, since it gives such weird results in creating transparency, [complimentary color establishes transparency amount and tint] in the book I reverted exclusively to the Transparency Class shader "Plain Coverage" that establishes transparency by percentage.

Thank you all for discovering that it still casts a shadow - that is really important!

[Palawat]

Glad that works for you, David

IMHO, It only works for limited situation. If you have shadows that comes from more than one light source (sun + lamps), the result could be weird.

It'd be nice if we have bottons that say " Hide from camera but still create shadow" and " Hide from camera and not creat shadow" that we can click on.

At this point, we could just create a new materail that cast shadow only and name it something like....hideFromCamButCreateWeirdShadow. So that we can switch the object from the normal material to this one.

[Anonymous]

I'm not that familiar with lightobjects and how to make them. But, Dwight, we got our windowlights, right? Isn't there a way to remake these lights to give us sunhighlights on floor and so on? Not only soft light on neighbour roof / walls ?