Convex hull as proxy replacement

[marcus_friese]

Dear all,
I am just new in this group and would like to present myself shortly: I model historic buildings and landscapes in Germany, having a growing collection of timberframe houses and related objects. For rendering I use V-ray since 2022 and there are still many many things to discover for me. Now to my question:

When I use Chaos Cosmos objects as proxies (mostly plants), they come with perfect proxy replacers in the form of a solid element that looks like convex hull of the original object (simple geometry).This hull is perfect to get an idea of the rendered model and its dimensions in relation to the scene. But when using own downloaded models as proxies, I can just choose between very poor displaing modes (boxes, polygon reductions that look nearly transparent for trees etc). I already read that I can replace the proxy by my own model, but I still did not find a suitable tool to create the replacement skp in a quick and proper way. I am looking for something creating convex hulls around my non-solid plant models: Light geometry, preferably as a solid, but with clearly distiguisable 3D borders. Once I have a solid convex hull, it would be easy to reduce polygones, but I strugle in creating the convex hull. I have Transmutr and Artisan, but both do not deliver me requested feature, at least for plants.

Kind regards,
Marcus

[natalia.gruzdova]

Hello marcus_friese and welcome to the Chaos Forums!

Could you please share some examples of results you are currently getting and the ones you are looking for?

Cosmos Assets are cross-platform models and for most cases low-poly previews are created customly by our 3d artists in different applications.

Using V-Ray you have an option to export your model as .vrmesh and choose between Preview Types: you are welcome to read more in our documentation. I also wanted to point out that there is an interesting way in SketchUp how you can save this .vrmesh as .vrmat to create your own assets library - please check this tutorial on how it can be done.



As for the Transmutr it seems to work fine with Simplified geometry Placeholder type to reduce face count and at the same time the object stays distinguishable.

[marcus_friese]

Dear Natalia,
sorry for my late reply. My post was a bit missleading as I asked for plants, but I meant espacially big ones (bushes and trees, no need for smaller indoor plants). I try to demonstrate my issue with a picture:
You can see a typical mixture of chaos chosmos assets and own models (bought in different shops):
The Chaos Chosmos Asset tree on the left side (Geometry "low") is simple and solid, easy to handly and representative for the final result.
The replacement geometry of my further models (preview faces, 10.000) looks somehow hazy, big trees are sometimes hardly recognizable in the Sketchup work environment, foilage and truncs. Further the replacement geometry differs a lot between the models depending on their specific geometry (low vs. high poly) and they are incredible heavy if you use a lot of vegatation.
When designing complex garden environments, I have problems to get a feeling for a good placement of the plants when using own proxies as their appearance is so far away from the final result (boxes are even worse!). All that would be solved for me if I could build easily convey hulls of lets say trees as replacement geometry.
Long story, short question: Is there a tool available that quickly turns trees and bushes (non solid!) into a convey hull -like solid form? All geoetry simplifiacation tools I know just lower the amount of polygons leading to trees loosing their foilage. Thanks for your help in advance!

[natalia.gruzdova]

Thank you marcus_friese for clarification.

Unfortunately for now there are two things that has to be taken into account:

• Even if you are able to create a custom proxy mesh preview - it is not currently supported in V-Ray for SketchUp.
• As I have shared before, the preview for Cosmos Assets is created specifically by our artist in different DCC, and basically it is different geometry. They adjust models and create Low, Medium and High LoDs (Level of Details) to choose from. Most of the optimization apps or extensions you can find work with the existing mesh and just simplifies it (exporting .vrmesh as well).

I apologize that we are not able to provide any further solutions about your request at the moment.

[konstantin_chaos]

Hi marcus_friese,

There is actually one workaround that you can apply:

1) Import a proxy:

2) Change its preview type to Custom

3) Edit the proxy component in SketchUp by unlocking the inner group

4) Delete the existing geometry in this group and replace it with whatever you want:


At the end you should be careful not to change the preview type of the proxy again since this will delete your custom mesh.

Hope that helps,
Konstantin