Firstly, thank you for the amount of requests we have had asking us to put this together, we can finally release something that should not only help your workflow in general but also your understanding of OBJ files to proxy files. If you are finding the images to small, jsut click on them and they will re-open in a new browser.
– Please note that you will need an OBJ importer for any OBJ files and the ‘Material Replacer’ tool from Sketchucation.
Ok, lets get to it!
Start by importing your chosen tree model into sketchup. In this instance we have used an adult Hornbeam tree sourced from XFrog. This tree model was an OBJ. file so we have used simlab OBJ importer.
We must now rename all our materials for futureproofing, and ease of understanding.
By right clicking onto ‘Scene Materials’ we can then choose to create a new material, from the list we will need ‘2Sided’. It will appear as ‘defaultMaterial’ and have a set up like this.
Now we have our 2Sided material named we must assign the single sided material in both slots of the 2sided mat like above. Dont forget to play with transparency. For the sake of this tutorial we have opted for a mid-grey for roughly half transparency.
Applying the 2Sided material onto a rectangular face in this instance helps us see the texture in its entirety. We do this to check texture sizes. In this instance our single sided material on the tree is 25mm & our 2Sided material is 254mm. We must edit the size of the 2sided material to match the single sided material. So change this to 25mm.
Our 2Sided material is now the correct size to replace the existing single sided material we find on the tree. We must now find our ‘material replacer’ tool. This can be found following this path – tools/material replacer. Once the tool is selected we simply click on the material we want to replace first, then click the material we want to be replaced by (2sided). Now, with the bucket tool (B) we can select both the tree and the rectangle you see in the scene and if correctly done will now both be the 2sided material we had initially created.
We now must set up all the layers using the preferred maps and values. Remember, we can never set up a model exactly correct without seeing it within our scene, so the settings you are providing the model with must be taken generally. If you look at the preview ball closely you will see that a reflection layer adds reflection to the whole surface of the PNG diffuse map and not just the leaf template itself.
To eradicate this issue we simply use a PNG or a TIFF file or similar and place this in the perpendicular slot inside the TexFresnel window. To simplify, we have added a standard reflection layer, a TexFresnel roll out & then a TexBitmap which will contain our specular map. For further explanation, you should be able to use external software to create your maps, you may see here that we are actually using a grey-scale bump map as our specular map. This is fine if we only require a soft and subtle specular effects.
Now we must set up all the other standard materials with their specifics using any normal/bumps, speculars & masks if needed. Remember again, these settings are to be general, each and every scene you ever import this model into will be different. It’s important that we set up the materials to the best of our knowledge but also think about draft render times. There is no point setting your leaf subdivs to a stupidly high value like 64 because on every single import in the future you will have to go to your materials and locate the 2sided material and lower their values to allow for efficient draft rendering. We have opted for 16subdivs for the leaf values. – We now see with the TIFF file used for the leaves, the reflection has only effected the leaf template of the preview.
Our SKP model setup is now complete. Zoom extents and save this file with an appropriate name and path.
Let’s now render our model to check everything is in order before we proceed onto the proxy stage. We should now be able to see clearly the effects that the 2Sided material is having on the model. Please remember that if the 2Sided material has no light coming through the face, then no effect will take place. You can see we have rendered our scene looking slightly toward the sun to show off the effects more accurately.
Now we have correctly been able to render the model and witness the effects of the 2Sided material working in the direct sunlight, we can save out the render as a PNG file. This is very important that it is saved to a transparent layer like PNG. We will be using this image later on in the tutorial.
Here we start the proxy process. Please double check your axis points, it’s absolutely crucial that your axis are correct BEFORE producing your proxy, this will help with any scattering processes later on down the line for various projects. We have confirmed all our materials are working and assigned correctly so now it is time to create a proxy and reduce the poly-count and general interface speeds. Select the tree and export as a Vray proxy using the Vray tools bar. We can ignore these options you see regarding triangle count as we will later be creating our own 2D face to insert into the proxy model.
Once the proxy exportation process is complete you will see a similar proxy model with numerous triangle counts. Enter the proxy component all the way down to its base layer and import the PNG we rendered out in step 13 as an ‘IMAGE’.
Once the PNG file is in, drop it next to the proxy model and try to replicate its exact size by moving it into the centre of the proxy. Rotate the view to really get the image to fit the proxy size.
Copy and then paste in place the same PNG and rotate it to form an intersected image.
We must now completely exit the proxy model grouping and make sure what we have done is successful. Render off a low resolution image to check that the new proxy formation we have made with the 2 PNG images renders like the original model did in step 12.
Now we zoom all extents and save this file OVER the proxy file we created in step 14 & 15.
Congratulations guys, you should now have a fully working proxy, we must now open a new empty file and import the proxy through SKETCHUP import. – Scroll through your PC and find the correct file. It should be named V-Ray proxy – (your allocated name), this is a SKP file you can use in any scene you wish. Remember though, dont go changing your material paths because all your proxies you have created with those, will become obsolete.